Audiences tuning into the FireAid benefit concert for Los Angeles on Thursday night (Jan. 30) were surprised with an early treat when pop superstar Billie Eilish made a surprise appearance alongside Billie Joe Armstrong and the rest of Green Day for a stirring opening performance.

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.

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.

A lineup of A-list artists is set to perform in the FireAid concert on Thursday, Jan. 30, benefiting the victims of the deadly Los Angeles wildfires . Billie Eilish, Olivia Rodrigo, Lady Gaga, Jelly Roll, and Stevie Wonder are some of the mega stars slated to take the stage.

"From the bottom of our hearts, we love you Los Angeles," Billie Joe Armstrong told the crowd, "and we've got your back no matter what"

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.