When thinking of TV shows that featured a ton of Hollywood star power, not everyone's initial thought is How I Met Your Mother. For the most part, we're usually thinking of Friends or Entourage in terms of how many celebrities we saw appear over the course of their seasons. However, Ted, Marshall, Barney, Lily and Robin did meet their fair share of famous people throughout their 9 season run. In fact, one could even call Robin a celebrity, if Canadian pop stars are their thing!

In today's list, we will be looking at 20 different celebrities who showed up on How I Met Your Mother. While some of them only had a line or two, others actually had storylines that persisted through more than just one episode. Let's start counting down these stars and see just how many everyone remembers watching!

20 Oh, Honey! Is That Katy Perry?

Katy Perry - HIMYM - Cameo
via seriously.com

Katy Perry was just one of the celebrities that came around in season 6. In an attempt to disguise her feelings for Ted, Zoey set him up with her cousin - Katy Perry. Of course, her name wasn't Katy Perry, but since she was so gullible the gang just called her Honey.

19 Barney Barker

Bob Barker - HIMYM - Cameo
via imdb.com

The legendary host of The Price is Right popped up in season 2. Barney grew up thinking that Bob Barker was his father. After years of studying, Barney finally got onto the game show and nailed every single round, even winning both Showcases. However, he couldn't work up the nerve to confess to Bob that he believed he was his father.

18 Enrique Iglesias Had Everyone Swooning...Especially Marshall

Enrique Iglesias - HIMYM - Cameo
via pinterest.com

After Robin and Ted ended things (the first time), Robin took a trip and met the handsome Gael. Portrayed by Enrique Iglesias, Gael had a knack for making everyone fall for him within moments. As we can see by Marshall's face, not even straight men are immune to Iglesias' magic.

17 Kim Kardashian Supported Marshall In A Big Way

Kim Kardashian - HIMYM - Cameo
via prosieben.at

While working for GNB, Marshall was faced with a troubling dilemma. He needed to "read a magazine", but was uncomfortable doing so in one of the employee bathrooms. He would go anywhere else he could find, but clearly, this was a problem. However, Kim Kardashian appeared on one of his magazines and gave him just the pep talk he needed!

16 Ted Inspired Weird Al Yankovic

Weird Al - HIMYM - Cameo
via prosieben.de

In season 7, Ted remembered that he once wrote to Weird Al, suggesting new material for him to use in his music. Later on, we get a flashback scene of Weird Al opening Ted's letter back in 1985. Ted had proposed the song "Like a Surgeon" and obviously, it was a hit.

15 Barney Tried To Marry Ted And Ashley Benson

Ashley Benson - HIMYM - Cameo
via barneystinsonblog.com

Ted dated many women throughout the course of the series, but Carly Whittaker (Ashley Benson) was one of the more memorable ones. Why? Because she was Barney's half-sister! While Carly was ultimately too young for Ted, Barney did try to rope them into marriage, since you know, he's so against one night stands and everything...

14 Alex Trebek Hosted Million Dollar Heads Or Tails

Alex Trebek - HIMYM - Coin Toss
via bustle.com

When How I Met Your Mother needed a new host for their fictional game show Million Dollar Heads or Tails, they knew there was only possible man for the job. Alex Trebek! The beloved Jeopardy! host appeared in 2 separate episodes, as he was also needed for a Canadian Robin Sparkles storyline.

13 Britney Spears Had A Thing For Ted

Britney Spears - HIMYM - Cameo
via tvandmovienews.com

Britney Spears played Abby, the receptionist at Stella's work. She showed up in two separate episodes and made it extremely clear she had a thing for our guy Ted Mosby. When Ted didn't return her feelings, Abby wound up spending the night with Barney instead. Obviously, that didn't really work out for her either.

12 Alan Thicke And Robin Go Way Back

Alan Thicke - HIMYM - Robin Sparkles
via people.com

Alan Thicke actually appeared several times throughout the series. Whenever there was a Robin Sparkles throwback, Thicke usually popped up. Afterall, he was one of her closest Canadian friends. That being said, he obviously had to accept the invitation Barney sent him to attend his and Robin's rehearsal dinner.

11 Carrie Underwood Had Ted On Her Hook

Carrie Underwood - HIMYM - Cameo
via pinterest.com

The famous country singer came around in season 5. She played Tiffany, a woman Ted was very much interested in, though she was more into keeping him around as a backup. Once Ted realised this, he stepped back and saw that she too was being kept on someone's hook, and that he had someone on his as well.

10 Nobody Cures The Yips Like Heidi Klum

Heidi Klum - HIMYM - Cameo
via ok-magazin.de

In season 3, Barney scores tickets to a Victoria's Secret Fashion Show After-Party. As happy an occasion as this should have been, Barney wound up coming down with a nasty case of the yips. However, Heidi Klum appeared at the party and was able to give him just the advice he needed to get back to his normal self.

9 Laura Prepon Was The WORST

Laura Prepon - HIMYM - Karen
via ew.com

Ok, so we have nothing against Laura Prepon, but her character Karen is a totally different story. Karen was Ted's college girlfriend. Lily and Marshall hated her and this hadn't changed by the time she and Ted were giving things another go in their adult years. We love college Ted, but Karen is just the worst.

Related: Whisper: 15 Real Life 'How I Met Your Mother' Stories That Are Scandalous AF

8 Regis Philbin Loves Burgers

Regis Philbin - HIMYM - Cameo
via people.com

Regis Philbin was actually the original host of Million Dollar Heads or Tails, but his most memorable contribution to How I Met Your Mother was no doubt his thirst for the perfect burger. Marshall had been searching for the same burger and Regis for years and when they finally found it, the moment was glorious.

7 Jennifer Lopez Is Anita Appleby

Jennifer Lopez - HIMYM
via weheartit.com

Jennifer Lopez played the role of Anita Appleby. She was a relationship expert who had written several books and even appeared on Robin's morning show. Robin tried to use Anita to bring Barney down a notch or two, though things didn't exactly go to plan. Anita was simply no match for the Barnacle.

6 Judy Greer Loved The Wedding Bride

Judy Greer - HIMYM - Cameo
via popsugar.com

Who could ever forget about The Wedding Bride? When Ted first saw the movie, he was dating Royce, played by Judy Greer. Royce, along with the rest of the world, loved the movie. While Ted naturally hated it, the film did make him realize that he was carrying around quite a bit of relationship baggage.

Related: 15 Terrible Gags In 'How I Met Your Mother' (That Made Us Uncomfortable AF)

5 Katie Holmes Rocked That Pumpkin Costume

Katie Holmes - HIMYM - Cameo
via dailymail.co.uk

We waited a long time for Ted to meet "the one that got away". After falling for a girl in a risqué pumpkin costume at a Halloween party, Ted spent the next few years searching for her. When she finally showed up, it was Katie Holmes! While the relationship failed as quickly as his others, it was nice to finally see him close that chapter.

4 Maury Povich Is A Great Celebrity Sighting

Maury Povich - HIMYM
via movieplayer.it

Even though Robin was excited over seeing the famous Maury Povich, the rest of the gang was not. Apparently, seeing Maury Povich around New York City is not that uncommon of a thing, though to Canadian-born Robin, it was an awesome celebrity sighting. Who wouldn't want the chance to meet Maury Povich?!

3 We Can Thank Mandy Moore For Ted's Butterfly Tattoo

Mandy Moore - HIMYM - Cameo
via imdb.com

The morning Ted woke up with a butterfly tattoo on his lower back, was one of the best moments out of the entire series. The gang all gathered to take a look at the masterpiece and while Ted did eventually have it removed, those memories are for life. Mandy Moore was the girl who brought Ted to the tattoo parlour and for that, we are so thankful.

Related: Ranked: All Of Ted's Relationships On How I Met Your Mother, From Worst To Best

2 Robin Sparkles & Jessica Glitter

Nicole Scherzinger - HIMYM - Robin Sparkles
via eonline.com

Each episode that featured Robin Sparkles was magical. After watching her many music videos, the gang eventually discovered a Canadian television show that Robin Sparkles had been part of. This time around, she had a partner - Jessica Glitter. Jessica was played by Nicole Scherzinger. The two used their show to teach kids about math in the most inappropriate ways possible.

1 Lucy Hale Is Robin's Sister

Lucy Hale - HIMYM - Cameo
via popsugar.com

We actually saw Lucy Hale a couple of times throughout the series. She played Katie Scherbatsky, Robin's younger sister. While she was never given storylines as big as say Barney's brother, she did pop up whenever necessary. We love the Scherbatsky women, though their father definitely did a number on them...

Next: 15 Things You Never Noticed In 'How I Met Your Mother'