T.R. Knight joins 'Parade' musical

Plot based on the true story of Leo Frank

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

"Parade" opens Sunday at the Mark Taper Forum in Los Angeles. The musical is based on the true story of Leo Frank, lynched for the murder of a young girl who worked in the factory he managed. Knight plays Frank.

The 36-year-old actor says he's grateful for everything he learned on the ABC medical drama. Knight says he watched the season premiere, which bid goodbye to his character, Dr. George O'Malley.

Knight says it was "a beautiful episode."

The Center Theatre Group production of "Parade," directed by Rob Ashford, comes from London's Donmar Warehouse