Sandra Oh has announced she will leave 'Grey's Anatomy' after its tenth season.

The 42-year-old star - who plays Dr. Cristina Yang in the long-running hospital drama - feels it is time to move on from the role she has played ever since the show's inception in 2005.

She told The Hollywood Reporter: ''Creatively, I really feel like I gave it my all, and I feel ready to let her go. It's such an interesting thing to play a character for so long and to actually get the sense that she wants to be let go as well.''

Sandra explained it is now time for the show's bosses to begin creating her farewell storyline and decide her character's motivation for leaving.

She added: ''[Cristina] wants to be let go, and I am ready to let her go. We have to start the process, story-wise, for the Grey's writers to think of why she's going to go.''

Despite the sad news for both Sandra and her fans, she insisted her exit should be a ''celebration'' of Cristina.

She said: ''I want this to be a celebration. I want us to get to that point where we see this character ride off into the sunset.

''Letting go of such a huge part of my life ... I want to cry right now. 'Grey's' has been the most important role of my life.

''Playing Cristina and growing her and growing myself in her, I want to usher her into the next section of her life in the best way possible. It's got to be Cristina Yang's happily ever after.''