Vice President Joe Biden made a surprise appearance at Sunday night’s 88th Academy Awards to speak out against sexual assaults on college campuses.

Biden introduced a performance by pop star Lady Gaga, whose song “‘Til It Happens to You” was nominated for an Oscar. The song was featured in The Hunting Ground, a 2015 documentary about young women who have been sexually assaulted on college campuses.

Biden, who has been actively involved in the issue and wrote the Violence Against Women Act in the early 1990s, told the Oscars audience to “take the pledge” to “change the culture” that makes college campus assaults so prevalent.

onstage during the 88th Annual Academy Awards at the Dolby Theatre on February 28, 2016 in Hollywood, California.
Vice President Joe Biden onstage during the 88th Annual Academy Awards, introducing Lady Gaga.Photograph by Kevin Winter—Getty Images

Lady Gaga’s performance—featuring a stage full of sexual assault victims—ended up being one of the night’s most talked-about moments on social media even though her song eventually lost the Best Original Song award to Sam Smith’s “Writing’s On The Wall” from the James Bond film Spectre. On Monday morning, “‘Til It Happens to You” ranked just ahead of Smith’s song on Apple’s AAPL iTunes Charts (the songs ranked 13th and 14th overall, respectively).

Meanwhile, fellow pop star Kesha—who is currently embroiled in a legal drama with Sony Music and her former producer, whom she has accused of sexually abusing her—tweeted to thank Biden and praise Lady Gaga’s performance last night:

Lady Gaga, who is also a victim of sexual assault, had previously tweeted her support for Kesha in her ongoing legal battle.

The Academy Awards aired on Walt Disney’s DIS ABC on Sunday night.