While the current (crazy) season is going down now, Grey’s Anatomy is gearing up for their thirteenth season after what has been 12 crazy-filled years. Loaded with nothing but plot twists, changing characters, and of course guest stars, Grey's is the kind of show that rips your heart out and we all just keep coming back for more. It was just announced that Wilmer Valderrama from That '70s Show is set to join the cast later in April as they finish off their twelfth season, and we couldn’t be more excited about it.

In honor of Grey’s Anatomy welcoming a new actor to the cast, we are looking at our favorite guest stars from over the years. Let’s get it started!

5.| Holland Roden

Hey all you Teen Wolf fans out there! Did you know that Holland Roden guest starred in an episode of Grey's back in 2012? She played a mother who had conjoined twins that were undergoing an operation to be separated. It’s a very dramatic clip from an incredibly intense procedure, but in the end the babies turned out to be just fine, resulting in a happy Holland.

4.| Sarah Paulson

Any American Horror Story followers around? You have to check out AHS regular Sarah Paulson in Grey’s as Dr. Ellis Gray in a season 6 episode of the show. The episode is all about flashbacks to prior cases and studies the doctors have worked on, and we see Sarah Paulson working on diagnosing (what is now called) HIV.

 

3.| Scott Foley 

With his charm and good looks, it’s no surprise that Scott Foley landed a role playing a lovable patient (Henry Burton) who Dr. Teddy Altman decides to marry in order to help him get the health insurance and care that he needs. Obviously this fake marriage turns into something more (I mean seriously, who wouldn’t fall in love with this guy?) and Teddy ends up developing deep feelings for Henry. However, like in true Grey’s fashion, this doesn’t really have a picture-perfect ending like we all hoped it would. Thanks Shonda Rhimes for ripping out our hearts, one cute actor at a time. 

 

2.| Mandy Moore

If you haven’t seen the season 6 finale of Grey's, you seriously need to. It is by far one of the most intense episodes arguably they have ever done, and I’m still not over watching it (and it’s been like, six years since it’s debuted.) Mandy Moore was introduced into the series as a nurse who helps out Dr. Bailey in the final episode of the season, returning later in the next season to catch up with her character. The poor girl pretty much never catches a break when she’s on this show, but it makes it all so entertaining to watch.

1.| Demi Lovato

Topping off our list of favorite guest stars on the dramatic show is Ms. Demi Lovato! The girl is a crazy good actress and her character was so interesting that it couldn’t not make our list. As if season six wasn’t insane enough, they filled it with episodes like this one that have such amazing storylines that get you hooked to each character, especially like Demi in this ep.  

Who are your favorite Grey's Anatomy guest star? Let us know!