"Grey's Anatomy" star T.R. KNIGHT is gearing up to take the stage for "Good Medicine," a concert being held this Friday at UCLA to benefit The Solidarity Fund, and ET is exclusively at his rehearsal -- where he admitted he was "scared, very scared," of performing.

The Solidarity Fund was set up by the Writers Guild of America to help crew members who lost work due to the three-month strike. Friday's benefit will also feature performances from a number of T.R.'s castmates, including KATHERINE HEIGL, SARA RAMIREZ and ELLEN POMPEO as well as "Private Practice" stars AMY BRENNEMAN and TIM DALY, among others. Tickets are available at Ticketmaster.com.

Meanwhile, T.R. also offered a few "Grey's" tidbits, set to return to the airwaves April 24 on ABC. "Someone's going to die," he jokes. "I bet that's going to happen!"

Kidding aside, T.R. does say that it will be quite a challenge for the writers to close up the season. "They've got to take those storylines and somehow condense all that -- 12 different peoples' journeys into 5 episodes."