Everyone knows Ariana Grande. The mega-famous, Florida-born pop star keeps fans guessing with her ever-evolving mixture of pop music, R&B, ballads, and Broadway-style covers. Some people may have also heard of talented singer and actress, Elizabeth Gillies, better known as "Liz." She is the star of the CW's remake of the drama, Dynasty, where she plays an ultra-rich Atlanta businesswoman.

What most people may not know is that the two are extremely close friends. Ariana and Liz got their start on Broadway when they were cast in the musical, "13", They were both 14 years old. Their friendship has spanned the years and it's a friendship filled with immense support and admiration.

In 13 years, they have never once made headlines for a petty spat or argument. On social media, they show nothing but love for each other and are seen hanging out...usually, a few times a year.

Here are 20 things that may surprise most people about Ariana Grande and Liz Gillies's friendship.

20 They Met While On Broadway Together

Looking at Ariana Grande now, with her latest R&B and pop albums, most people wouldn't realize she first stepped into the spotlight as a Broadway kid. At 13, she was cast as Charlotte in the musical, 13, alongside Elizabeth Gillies. The two used to share stories of their time on Broadway, swallowing cough drops and herbal tea to keep their voices in good shape.

19 They Used To Live Together

Living with someone can either make or break a friendship. In this case, it made the friendship stronger. Liz lived with Ariana and her mom for a while, during their time as teen stars. In what seemed like an endless sleepover, the two used to stay up late posting videos of themselves singing and laughing on social media.

18 Their Friendship Solidified on Victorious

While their friendship did begin on Broadway, they grew closer after being cast as polar opposites—Cat and Jade—in Nickelodeon's, Victorious. Rumors surfaced for years that Ariana had petty drama with the lead of the show, and fellow co-star, Victoria Justice. Liz and Ari's friendship, however, remained strong.

17 They Used To Make A Million Livestreams

Both during and after their time living together, Ari and Liz spent hours recording themselves sitting in Ariana's room. They wrote "truth or dare" on pieces of paper and played in front of the camera, or sang Broadway songs, or prank-called their mutual friends.

16 Their Break Into Music Came From Victorious

While neither star was the lead of Victorious, they were fan favorites among Nickelodeon audiences everywhere. In a later episode of season one, the two had their first and only duet om the show. They sang the now-iconic, "Give It Up", for a "karaoke" episode...and their voices blended so well that fans were blown away.

15 They Got Their Drivers Licenses Together

Working in Hollywood doesn't always leave much time for normal teen activities. In June of 2013, the 17-year-old actors went to the DMV to take their driver's tests together. Luckily, they both passed their tests. Ariana took to Twitter to joke about the dangers of her driving home after.

14 They Form A Trio With Former Co-star Matt Bennett 

Ariana Grande, Liz Gillies, and Matt Bennett were inseparable at one point. For anyone following them on social media from 2009 to 2013, they seemed to be constantly together. Ari and Liz met Matt on the set of Victorious, where he played the love interest of Ariana's character, Cat. Ariana posted this reunion photo of them backstage during her Sweetener tour show in Atlanta.

13 They Perform Musical Theater Hits Every Chance They Get

Throughout the years, Ariana and Liz have delighted fans by performing duets and singing together every chance they get. As former Broadway kids, their song selections usually (and obviously) include other Broadway hits.

Earlier this year, they both posted videos on social media of them singing tunes from Rent at Ariana's house. They had a piano, mics and a complete sound system set up for the occasion.

12 They Once Dressed Up As Each Other For Halloween

As many best friends often do, Ariana and Liz spent Halloweens together. One year, in 2011, they decided to delight friends by dressing as each other's characters from Victorious. Ariana wore a dark-haired wig (much like her natural hair) to look like Jade, and Liz wore a red wig to look like Cat.

11 They Visited Hollywood Together For The First Time

Hollywood is a magical place for any aspiring singer, actor or born performer. Neither of these leading ladies could have predicted 10 years ago, when they first visited Hollywood, that they would become famous. Liz Gillies posted a picture on Instagram, explaining how much it meant for her to be reunited with her good friend, Ariana, and Joan Grande, Ariana's mother.

10 Liz Appeared On Ariana's First Christmas Album

Ariana's first Christmas album, "Christmas and Kisses", was released in 2013. The album only featured four songs, but one of them was a duet, "Santa Baby", with Liz Gillies. This wasn't the first time the two teamed up for a Christmas song. Ariana posted a video of them singing "Chestnuts Roasting on an Open Fire" in 2011.

9 Ariana Once Posted A Video Of Them Kissing

Everyone talks about times stars broke the Internet. For the majority of Millennials, this was one of those times. Ariana posted a video in 2015, "by accident", of the two of them kissing... immediately followed by roars of laughter. Liz commented back in all capitals saying, "HA HA HA. THAT GEM."

8 One Time They Sang The Drake And Josh Theme Song Together

Behind the scenes action on the set of Victorious often featured the cast singing, laughing and joking together. Liz and Ariana have a variety of charming backstage videos. While getting ready together on set one time, they began singing Nickelodeon's Drake and Josh theme song. Ariana mentioned the song again in 2017 on Twitter, saying it's "fire."

7 Liz Was In The "Right There" Music Video

"Right There" was a song from Ariana's first album, Yours Truly. It featured rapper Big Sean on the track and Liz Gillies in the video. Ariana Grande has a habit of including her friends in her music and videos. Liz appeared in the video, pretending to put on makeup with Ariana in front of a mirror.

6 They Had A Sleepover With Their Victorious Co-stars

Whether actually sleeping and staying over was involved, it's certainly clear that Ariana Grande, Matt Bennett, Liz Gillies, and fellow former co-star, Leon Thomas III, had a sleepover of sorts. It was complete with a tiger-striped blanket and some semi-awkward poses. Liz joked on Twitter that it was "Leon's first time."

5 Ari Brought Liz On Stage During Sweetener For "Give It Up"

Victorious fans everywhere were shaken to the core when Ariana brought out her longtime friend, Liz, for a reprise of the infamous "Give It Up" duet. During the second leg of the Sweetener tour, Ariana did a show in Atlanta, where Liz films her show, Dynasty. Matt Bennett was also at the concert, and went onstage to reprise his role as Robbie, by serenading Ari with, "I Think You're Swell."

4 Liz Danced In The "Thank U, Next" Video

Ariana upped the stakes for her five-and-a-half-minute video for the hit single, "thank u, next." She included a handful of some of her closest friends, including Liz Gillies. Liz played the iconic role of Cady Heron in the video and said that she almost didn't make a cameo, because of a spider bite on her face from the day before.

3 They Attended An SNL Afterparty Together

Ariana appeared on Saturday Night Live for the first time in 2016 as both host and guest artist. She performed her hits"Be Alright" and "Dangerous Woman", and participated in a variety of musically-focused sketches. What most do not know is that Liz accompanied Ariana to the SNL afterparty.

2 Ari Visited Liz On The Set Of Dynasty 

After the Sweetener show in Atlanta, Ariana hung around for a couple of days, to hang out with her good friend, Liz. She visited her on the set of Dynasty, where they are filming season three. Liz posted joyful photos of the two backstage to her Instagram Stories. It was a reunion-filled few days for the two old friends.

1 Liz Danced On Stage In Atlanta For "Thank U, Next"

As if singing together wasn't enough, Ariana also sang "Thank U, Next" at the Atlanta Sweetener concert, while Liz Gillies danced alongside onstage. Fans were ecstatic to see the two sharing hugs and joyfully strutting to the hit song. Also at this show was Senator Bernie Sanders, who Ariana openly supports.