It's been 12 years (crazy, right?!) since Grey's Anatomy premiered on ABC and the Grey Sloan Memorial surgeons stole our hearts forever. Since Grey's is still our favorite show today, we're taking a trip down memory lane to see how much the hit medical drama's cast has changed over the years. Scroll down to see Ellen Pompeo, Patrick Dempsey, Kate Walsh, and more stars then and now!

Ellen Pompeo (Meredith Grey)

Ellen — who received a Golden Globe nomination in 2007 for her portrayal of Meredith — continues to appear on the show today. The mom-of-three's notable film credits include Moonlight Mile, Old School, Daredevil, and Catch Me If You Can.

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Patrick Dempsey (Derek Shepherd)

In addition to playing Derek on Grey's, the actor is most recognized for appearing in movies Can't Buy Me Love, Sweet Home Alabama, Enchanted, Transformers: Dark of the Moon, and Bridget Jones's Baby.

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Justin Chambers (Alex Karev)

Justin is one of few original cast members to still be on the show after more than 10 years. Though he is most recognized for playing Dr. Karev, he has also starred in movies Broken City, The Zodiac, and The Wedding Planner.

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Sandra Oh (Cristina Yang)

The Golden Globe winner left Grey's in 2014 after appearing on 220 episodes. She recently appeared in the comedy Tammy and guest-starred on the TV show Betas. In summer 2017 is was announced that Sandra will play the target character in BBC America’s upcoming serial killer spy drama Killing Eve.

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Katherine Heigl (Izzie Stevens)

Since her run on Grey's came to an end in 2010, Katherine landed leading roles in movies Life as We Know It, New Year's Eve, 27 Dresses, The Ugly Truth, and The Big Wedding. The mom-of-three — who is married to musician Josh Kelley — was recently starring on TV shows State of Affairs and Doubt, but both series were unfortunately canceled.

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T.R. Knight (George O'Malley)

Though he has appeared in several TV shows and movies since playing beloved character George on Grey's, T.R. is most known for his Broadway performances. The actor most recently starred in the show It's Only a Play.

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Kevin McKidd (Owen Hunt)

After portraying Owen, Kevin appeared in the TV special Toy Story That Time Forgot. The actor — who recently split from his wife — has also voiced characters in the Grand Theft Auto and Call of Duty video games.

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Chandra Wilson (Miranda Bailey)

The mom-of-three's film credits include Philadelphia, Lone Star, and A Single Woman. In addition to Grey's, the star has also appeared on TV shows The Cosby Show, Law & Order: Special Victims Unit, and The Sopranos, among others.

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James Pickens Jr. (Richard Webber)

James is widely known for playing Dr. Webber on Grey's and Deputy Director Alvin Kersh on The X-Files. He has been awarded a SAG Award for his performance on the medical drama, which he continues to star on today.

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Isaiah Washington (Preston Burke)

After he left the show in 2007, the actor joined the cast of The 100. The father-of-three has also recently appeared in movies Blue Caprice, Doctor Bello, and Blackbird.

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Kate Walsh (Addison Montgomery)

After playing Addison on Grey's, Kate starred on her own spin-off show, Private Practice, from 2007 until 2013. In 2014, she landed a lead role on the comedy Bad Judge, but it was canceled after only a few seasons.

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Eric Dane (Mark Sloan)

Eric — who is married to actress Rebecca Gayheart — sadly left his character Mark behind in 2012 and has since appeared in movies including Marley & Me, Valentine's Day, and Burlesque. The actor now stars on the TNT drama The Last Ship but recently took a break from acting to seek treatment for depression.

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Sara Ramirez (Callie Torres)

In addition to her starring role on Grey's, Sara has also acted on Broadway and won a Tony Award for her performance in 2005's Spamalot. She left the show in 2016.

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Brooke Smith (Erica Hahn)

The actress' most memorable performance was in the 1991 horror film The Silence of the Lambs. After leaving the medical drama after 25 episodes in 2008, Brooke guest-starred on Criminal Minds, Law & Order: Special Victims Unit, and American Horror Story: Asylum.

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Chyler Leigh (Lexie Grey)

Chyler — who has also starred in Not Another Teen Movie — sadly left the show in 2012. She then starred on the TV show Taxi Brooklyn and now plays Alex Danvers on The CW's Supergirl.

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Jessica Capshaw (Arizona Robbins)

In addition to Grey's, mom-of-four Jessica is known for playing Jamie Stringer on The Practice and for guest-starring on Bones and The L Word.

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Jesse Williams (Jackson Avery)

In addition to Grey's, the star's acting credits include Lee Daniels' The Butler, The Cabin in the Woods, Brooklyn's Finest, and The Sisterhood of the Traveling Pants 2. Sadly, Jesse recently split with his wife of five years, Aryn Drake-Lee.

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Caterina Scorsone (Amelia Shepherd)

In addition to Grey's, the actress and mom-of-two is best known for starring on the Lifetime crime drama series Missing and on the Grey's Anatomy spin-off Private Practice.

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