It's surprising to see which A-list stars have dated other celebrities in the past. In the '90s, favorite movie star Jennifer Love Hewitt briefly dated MTV's TRL host Carson Daly, and while the two celebs have gone on to date and have children with other people, fans forget that these two were once lovebirds.

Hollywood stars tend to date inside their realm, and it can become pretty awkward when they split and have to see one another at a red carpet event or even work with each other for a film or television show. In the early 2000s, TV teen drama The O.C. aired, and fans loved the fact that characters Summer Roberts, played by Rachel Bilson, and Seth Cohen, played by Adam Brody were together in real life. However, when they split, they continued to work on the show, even having to act out a scene where they got hitched. Yikes!

There are also the Hollywood couples that were just downright strange. Tom Cruise and Cher were once an item back in the late '80s, and pop star Pink once dated former N'SYNC member Joey Fatone.

Check out this list of celebrity parents that we forgot dated one another, and get ready to be surprised.

20 Tom Cruise And Cher

This one may sound out of the ordinary, but Tom Cruise and Cher were in fact a couple back in 1985, when the two stars met at Sean Penn and Madonna's wedding. After their initial gathering at Madonna’s wedding, Cher and Cruise reunited at the White House for an event and Cher told Entertainment Tonight how the two bonded. "A bunch of people who were dyslexic were invited to [an event], and Tom and I are both dyslexic. We didn't go out till way later, but there definitely was a connection there," Cher revealed. She also added that she's still friends with Cruise but doesn't get "the whole Scientology thing."

19 Matthew McConaughey And Sandra Bullock

Hollywood stars Sandra Bullock and Matthew McConaughey briefly dated back in 1996, when the two met on the set of their film, A Time to... Bullock was always humble about her relationship with the actor, but it appeared that the two would just wind up as good friends. In 1997, she stated that McConaughey has "become a powerful force in my life" and that "we have fabulous chemistry together," insisting that they were only friends. Bullock and McConaughey remain close pals and even shared laughs on the red carpet at the 17th Annual Hollywood Films back in 2013, where Bullock hugged both McConaughey and his current wife, Camila Alves.

18 Ryan Reynolds And Alanis Morissette

Alanis Morissette and Ryan Reynolds first met at Drew Barrymore's birthday party in 2002, and by 2004, the couple was engaged.

The singer would say rather odd things about their relationship, stating that she felt "so loved by him, in a trampoline kind of way" and Reynolds was like a "soul brother to me." But, after a three-year engagement, the couple split, and it's unclear what caused the breakup. Morissette ended up using her breakup to create the song "Torch" off of her album Flavors of Entanglement. She revealed to Access that the song was "really about my grief."

17 Kim Kardashian And Nick Cannon

Kim Kardashian has quite a long list of exes, and Nick Cannon is one of them. The two dated from the end of 2006 to the start of 2007, and the sudden split emerged when Cannon told The Howard Stern Show that the Keeping Up With the Kardashians star lied to him about a famous tape she made with rapper Ray J and its existence. Well, the tape came out in February 2007, and apparently, Cannon did not want anything to do with Kim and her new "rise to fame." Nick Cannon went on to marry and later divorce singer Mariah Carey, whom he had twins with, and in 2017, he had a third child with model Brittany Bell. Kardashian just recently welcomed her fourth child with rapper Kanye West via surrogate.

16 Justin Timberlake And Cameron Diaz

Justin Timberlake and Cameron Diaz dated for four years before calling it quits back in 2007. According to People, Diaz, who was nine years older than the former N'SYNC star, met in April 2003 at the Nickelodeon Kids' Choice Awards, and by July, she joined him on tour with Christina Aguilera. Throughout their relationship, they both battled constant allegations, and there was also debate on how the two would ever end up getting married since Cameron Diaz has stated multiple times that she isn't a fan of commitment. However, Diaz did not have to worry about Timberlake putting a ring on her finger since the two broke things off in 2007.

15 Jennifer Lopez And Diddy

Jennifer Lopez has had her fair share of dating A-list stars in Hollywood. She was married three times, and her love life has been filled with dating, engagements, and proposals. One of the men she notoriously dated was rapper Diddy back in the late '90s. The couple dated from September 1999 until February 2001 back when they were known as Jennifer and Sean. Together, they went through some tough times, including legal run-ins and more. In an interview, Lopez stated, "I never caught him, but I just knew. He'd say he was going to a club for a couple of hours and then never come back that night."

14 Johnny Depp And Kate Moss

Actor Johnny Depp and model Kate Moss met in 1994, when he was 31 and she was 24. The couple traveled all over the world and were not shy when it came to showing their affection in public. There were a few reports of the two getting into heated arguments in public, trashed hotel rooms, and bad tempers, but they continued on with their relationship for another four years until calling it quits. In 2012, Moss revealed that she cried for "years" after they split. "There's nobody that's ever really been able to take care of me. Johnny did for a bit. I believed what he said. Like if I said, 'What do I do?', he'd tell me. And that's what I missed when I left,'" Moss said.

13 Gwyneth Paltrow And Brad Pitt

One of the biggest couples in Hollywood in the nineties was Brad Pitt and Gwyneth Paltrow. The duo met in 1994, when filming the movie Se7en, but split in 1997. Paltrow revealed in a podcast interview with Girlboss Radio in 2017 that she was the one that ruined the relationship because she is at her most "vulnerable." She also explained why she associated success with relationships, stating, "Success to me is relationships that function really well. Where there is a beautiful feedback loop between people. I think without relationships of quality, you are not a successful person." Paltrow also stated that she's grateful she broke up with Pitt back then because the paparazzi weren't so crazy in the '90s.

12 Ashton Kutcher And January Jones

In 2009, actress January Jones stated in an interview with GQ that her first boyfriend in Los Angeles did not support her with her acting ventures. Later, it was revealed that the boyfriend she was talking about was none other than actor Ashton Kutcher. Jones stated, "[He] was not supportive of my acting. He was like; I don't think you're going to be good at this. He only has nice things to say now - if anything, I should thank him. Because the minute you tell me I can't do something, that's when I'm most motivated." During an interview with Watch What Happens Live with Andy Cohen, a viewer questioned her about Kutcher, however, she never did reveal if it was him she was talking about in her GQ interview.

11 Owen Wilson And Sheryl Crow

Before singer Sheryl Crow was engaged to Lance Armstrong, she dated actor Owen Wilson from 1999 to 2001. The two had a short romance, but they were seen attending many events, including the exclusive Vanity Fair Oscar Party together in 2000. One of Crow's songs was even said to be dedicated to Wilson, titled "Safe and Sound," off of her album, C'mon C'mon, and according to the album's notes, the song was an account of their relationship. Crow had a number of high-profile relationships, including dating Eric Clapton, 17 years her senior, and, of course, cyclist Lance Armstrong.

10 Jennifer Love Hewitt And Carson Daly

Former MTV Total Request Live host Carson Daly and actress Jennifer Love Hewitt dated briefly from 1997 to 1998, before Hewitt is said to have ended the relationship via her publicist. In 2000, Daly revealed that he was shocked about the surprising split and was "publicly humiliated" that she had her publicist call their relationship off. Carson told People that he “woke up to Howard Stern telling me my relationship with [Jennifer] was over.” However, the two appear to be good friends now, with Hewitt sharing this major throwback photo on social media, from when the pair attended the VMAs red carpet together back in 1998.

9 Nicole Kidman And Lenny Kravitz

Nicole Kidman and rocker Lenny Kravitz dated between 2002 and 2003, and just two years ago the actress revealed that they were even secretly engaged!

While the two remain friends since their breakup, (Kidman even works with Kravitz's daughter Zoe on the set of Big Little Lies), the actress let slip that the duo was once considered going to the altar. "I knew Zoe because I was engaged to her father," Nicole stated, adding, "It's all in the family! I love Lenny, he's a great guy." However, she told Vanity Fair that the two were just not ready to take their relationship that far. "It just wasn't right. I wasn't ready. We weren't ready," she said.

8 Sarah Jessica Parker And Robert Downey Jr.

Before Sarah Jessica Parker met and married actor Matthew Broderick, she dated another big named star: Robert Downey Jr. The couple dated for quite some time, from 1984 until 1991, and Parker admitted that she feared for Downey's life while he struggled with addiction. She told People, "I learned how to take care of myself. There was a huge amount of time spent making sure he was okay. At a certain point, I had the courage to say, 'I'm going to walk away and I'm just going to pray that you don't [pass away]." Parker also admitted that she wasn't aware of Downey's addiction for a long time.

7 Whitney Houston And Ray J

Rapper and reality television star Ray J dated legendary singer Whitney Houston at the time of her passing in 2012. Houston passed on February 11, 2012, after passing away from coronary artery disease. Speaking to reporters, Ray J stated, "I really miss my friend, you know, I really do. I'm still hurting." However, Houston's sister-in-law and manager told Oprah Winfrey that Whitney's final days were filled with her "looking for love in all the wrong places." And although she wasn't mentioning any names, it appears that she was talking about Ray J, and said, "The dream she [Whitney] was chasing was younger."

6 Kid Rock And Pamela Anderson

Kid Rock and Pamela Anderson had a very rocky relationship, dating on-and-off again from 2001-2007. The former couple was even married towards the end of their relationship, famously saying their "I Do's" on a yacht in July of 2006, but later, Anderson filed for divorce in November of the same year. There were speculations that the divorce stemmed from Anderson appearing on the movie Borat, but there are still lingering questions about what really led to the couple ending their marriage. In an interview with The Hollywood Reporter in 2018, Anderson stated that she never spoke to Kid Rock since the split.

5 Pink And Joey Fatone

Believe it or not, singer Pink went on a date with former N'SYNC member Joey Fatone. According to Celebretainment, when Pink was just 19 years old and on her first concert tour, she went on a date with Fatone. Although their date never blossomed into anything serious, Pink only has positive memories of her date night with Fatone. In an episode of "Carpool Karaoke" on The Late Late Show with James Cordon, Pink told Cordon of her past fling, "Joey Fatone used to come in my dressing room every day and visit with us, and he was such a sweetheart." Fatone later asked her father if he could take her on a date and two went to Friendly's where Pink got herself an ice cream. However, Pink stated that they were just in the "friend-zone."

4 Jennifer Garner And Scott Foley (Who Were Married!)

Jennifer Garner and Scott Foley met in 1998, when she guest-starred on two episodes of Felicity and starred as the long-distance girlfriend of Foley's character. The two hit it off and got married in 2000, but announced their separation in April of 2003. Did they split because Garner was getting too famous? The actress became a household name after landing the leading role on the hit show Alias. However, in an interview, Garner admitted that she and Foley "really were the victims of Hollywood," adding, "everything is speeded up here - it is a fast-lane life, and if something is not working, it is considered best to end it without much thought. If we lived where I was brought up, [West Virginia], we would probably still be together."

3 Rachel Bilson And Adam Brody

Adam Brody and Rachel Bilson were co-stars on the hit show The O.C. and fans of the show were extremely happy when Seth Cohen and Summer Roberts ended up dating in real life in 2003. The duo was adorable off-screen, but fans would later learn that their favorite television couple couldn't keep the fire going and split in 2006. While the couple broke up in real life, The O.C. still had to run its final season where Summer and Seth got married in the end. Rachel Bilson went on to date actor Hayden Christensen, while Brody found love again with another television actress, Leighton Meester, who starred in Gossip Girl.

2 Brooke Shields And Andre Agassi

Supermodel Brooke Shield was married to tennis pro Andre Agassi back in 1997, but the couple divorced just two years later. In November 2009, Agassi opened up about his failed marriage on the Today Show, stating, "I think at that time in my life I couldn't be married to anyone. I think timing is really important. You need in a marriage, two people who understand themselves ... and I certainly didn't understand myself." Shields addressed her divorce in 2013, saying, "I am divorced. And mine was fairly quick and relatively easy but it's a very interesting thing because he did say to me, 'Be happy that we don't have children or I would not have made this easy for you.'"

1 Hilary Duff And Joel Madden

Hilary Duff began dating rocker Joel Madden when she was just 16-years-old and he was 25, back in 2004. Madden even worked on Duff's compilation album, Most Wanted, but the couple wouldn't last long and split in November 2006. However, both Duff and Madden confirmed that they still had a "great relationship" even after they called it quits, with Madden telling People, "Every girl I've dated I have respect for, and I always try to leave them in good terms."

Since then, Madden went on to date and later marry Nicole Richie in 2010, and Hilary Duff just recently got engaged to her new beau Matthew Koma.

Sources: People.com, ETOnline.com, elitedaily.com, popsugar.com, marieclarie.com, eonline.com, instyle.com, news.com.au, usmagazine.com, celebretainment.com, zimbio.com.