Wow. If you thought Lady Gaga slayed her Sound of Music tribute at last year's Oscars, you're going to love her performance of "Til It Happens to You." She and Diane Warren were nominated for the track, which appeared on the soundtrack for The Hunting Ground. Both the film and the song are about a powerful subject: rape culture on college campuses. Just when you think the performance can't get any more emotional, Gaga is joined by an army of survivors on stage. Watch it now.