The “Shallow” singer closed out the star-studded benefit concert with a song she co-wrote for the show with her fiancé, Michael Polansky.

Billie Eilish made a surprise appearance on stage with Green Day on Thursday to kick off one of two star-studded concerts in Los Angeles put together to raise funds for people affected by deadly wildfires in California this month.

Pop stars, rock legends, first responders, and survivors of the devastating Los Angeles-area wildfires came together for FireAid, a benefit concert to help the area recover. View on euronews

Rod Stewart, Katy Perry and Lady Gaga were just some of the famous faces who performed at FireAid on Thursday, a benefit concert raising money for those affected by the devastating Los Angeles wildfires. The wildfires began on January 7 and spread rapidly, killing at least 28 people and destroying more than 10,000 homes.

Pink, who always dials it up to 100, performed Janis Joplin's “Me and Bobby McGee” and Led Zeppelin's “Babe I'm Gonna Leave You.” While introducing John Mayer, she addresses the crowd: “Ladies and gentlemen, and every other gender which absolutely exists,” seemingly a reference to President Trump's “two gender” declaration.

Pop stars, first responders, rock musicians, and wildfire survivors gathered for FireAid on Thursday night, a benefit concert to raise funds and share.

Sting, Billie Eilish, Rod Stewart, Stevie Wonder and Lady Gaga are among the stars performing at a huge benefit concert in Los Angeles to help the area recover from recent devastating wildfires.

Billie Eilish, Dr. Dre, Stevie Wonder, Green Day, Joni Mitchell, No Doubt and the remaining members of Nirvana all performed.

Some of the biggest names in music, including Billie Eilish, Lady Gaga, and Green Day, played FireAid at the Kia Forum and Intuit Dome on Jan 30.

Gaga altered lyrics to "Always Remember Us This Way" as she performed in support of relief efforts for the wildfires: "I love you CALIFORNIA," she later posted.

Green Day and Billie Eilish kicked off the massive FireAid benefit concert, a two-venue concert extravaganza that raised money for Los Angeles-area wildfire relief efforts.