Don't count on Patrick Dempsey singing along in the upcoming "Grey's Anatomy" musical event.
"I'm basically in the OR operating," Dempsey explained to "Extra" at the John Varvatos' 8th Annual Stuart House event. "I'm oblivious to everything."
But in real-life he is focusing on raising awareness with this event, which, as the actor tells us, "is known for helping children who are abused."
The special "Grey's Anatomy: The Musical Event" airs Thursday, March 31 on ABC.