Every actor who's ever left Grey's Anatomy – and why

It was originally reported that TR Knight left the show because he came out as gay following Isaiah Washington's alleged slur, but he insists that had nothing to do with it. "It was time to go. Looking back, I learned so much and it was so valuable," he explained. "There are times in anybody's job where you feel the best decision is to move on."

If you ask Brooke Smith, she would claim that she was written out because her character was in a same-sex relationship with Callie Torres (Sara Ramirez). However, Shonda Rhimes responded that they just "did not find that the magic and chemistry with Brooke's character would sustain in the long run".

Officially, Katherine Heigl left to focus on her family, but her exit came after a much-publicised controversy when she withdrew from the 2008 Emmy race because she didn't think her season five "material" warranted a nomination. Ouch. She returned for season six, lasting until episode 18 until she exited.

Having been made a series regular in season four, Chyler Leigh's Lexie Grey was tragically killed off in the season eight finale. But it was Leigh's decision to leave and she knew before the season started. "I met with Shonda and we worked together to give Lexie's story appropriate closure," she recalled.

The exit of Kim Raver's Teddy Altman in the season-eight finale surprised everyone, but it was just because Raver's contract was up and "she was ready to give Teddy Altman a much-needed vacation", according to Shonda Rhimes. Fortunately, Teddy returned in season 14.

The plane crash that killed Lexie Grey also marked the end for Eric Dane's Mark Sloan, although he at least appeared briefly in season nine. His exit though was so he could lead new show The Last Ship. "It was an opportunity for me to go and I was interested in something different," he explained. "I loved doing Grey's Anatomy. I would have done it until the final episode, but this was something I couldn't pass up."

Having been on the show since the beginning, Sandra Oh exited at the end of season ten and it was entirely her decision. "Creatively, I really feel like I gave it my all, and I feel ready to let her go," she explained. "[Cristina] wants to be let go, and I am ready to let her go."

Having first appeared as interns in season nine, Gaius Charles and Tessa Ferrer were promoted to series regulars in season ten, but that was their lot as their contracts weren't renewed for further seasons.

McDreamy's death in season 11 shocked fans, especially as Patrick Dempsey had signed on for season 12. However, he just felt it was the time to leave and thinks he probably should have left earlier. "It had been long enough. It was time for me to move on with other things and other interests," he noted. "I stayed a bit longer than I should have."

Shonda Rhimes might have been surprised by Sara Ramirez's exit, but it was at least done without any controversy. "Taking a step back from the industry has allowed me to take space and get even more clear about things that are important to me," Ramirez noted about her decision to take "some welcome time off". But she hasn't ruled out a return in the future.

Initially it looked like Jerrika Hinton would just spend less time on Grey's Anatomy after signing up to Shondaland's Toast, but then that show never went ahead. She did however nab a role in Here and Now, so decided to leave anyway. "Shonda and I had a meeting at the beginning of season 13 where we talked about my departure and my creative process, and she was very supportive of my wishes," Hinton noted.

Meredith Grey's first major post-McDreamy love interest was Martin Henderson's Nathan Riggs, but he knew all along that he would only be on the show for a little while. "I only had a short-term contract with the show," he explained. "[Season 14 was] my final year so I was expecting Nathan's storyline to be wrapped up."

Like with Kate Walsh, Jason George left Grey's Anatomy to take on a lead role in spin-off Station 19, but don't rule out guest appearances from him in Grey's in the future.

The exits of Jessica Capshaw and Sarah Drew at the end of season 14 were met with outrage from fans and cast members alike, leading to Ellen Pompeo having to deny she had anything to do with it and the official word from the show was it was all down to creative reasons. At least both of them survived.