T.R. Knight, who turned in his "Grey's Anatomy" scrubs earlier this year, is marching on with "Parade."

In the musical, which opens Sunday in Los Angeles at the Mark Taper Forum, Knight plays Leo Frank, who was lynched in real life for the murder of a girl who worked in the factory he managed.

Knight, 36, said he's grateful for everything he learned on ABC's "Grey's Anatomy." The Minneapolis native said he watched this season's premiere, which bid goodbye to his character, Dr. George O'Malley. "It was fascinating ... not knowing what was going to happen and being on that side of things," Knight said. "They do just beautiful, beautiful work. If that doesn't sound condescending, I was so proud of them."

Though Knight appeared in "Noises Off" on Broadway in 2001 and in the 2003 off-Broadway production of "Scattergood," he's never done a musical as a professional actor. "I did it when I was a teenager, but ..." he breaks out in song, "I'm not a teen-age-r an-y-more!" So he had to learn to act while singing.

Knight said he isn't sure what his next move will be after "Parade." The musical runs through Nov. 15. AP