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.

The all-star FireAid benefit in Los Angeles began with Green Day and Billie Eilish teaming up for the 'American Idiot' deep cut "Last Night on Earth."

The FireAid benefit was fueled by some of music’s best performers to raise money for Los Angeles-area wildfire relief efforts.

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

FireAid, a star-studded benefit concert raised millions for LA wildfire victims. The event featured emotional performances, including a surprise Nirvana reunion, Lady Gaga debuting a new song, and Billy Crystal hosting with humor.

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.

Raising money for ongoing wildfire relief efforts in Los Angeles, Green Day and Billie Eilish dueted 'Last Night On Earth' at the FireAid benefit concert.

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.

Billie Eilish and Finneas, Olivia Rodrigo, Earth, Wind & Fire, Gracie Abrams, Green Day, Jelly Roll, Joni Mitchell, Katy Perry, Lady Gaga, Lil Baby, Pink, Red Hot Chili Peppers, Rod Stewart, Sting, Stevie Nicks and Tate McRae are among those performing at the dueling shows at L.

Billie Eilish joined Green Day on 'Last Night on Earth' to kick off the FireAid concerts in Los Angeles to benefit wildfire relief in the city.

Green Day kicked off the massive FireAid benefit concert Thursday night, a two-venue concert extravaganza that is raising money for Los Angeles-area wildfire relief efforts.