Grey's Anatomy's upcoming Season 6 finale will feature a famous face: Mandy Moore.

The 25-year-old singer-actress will play Mary, a patient being treated by Bailey (Chandra Wilson) in the show's much-anticipated May 20, game-changing finale.

Sources said Moore is just one part of the kind of finale that executive producer Shonda Rhimes loves keeping under wraps, so no further details are available yet.

Any theories are welcome below!

Are you excited to see Mandy Moore on Grey's Anatomy?

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