"California, Los Angeles, Altadena, the Palisades - we are in this together," Green Day's frontman Billie Joe Armstrong screamed to a sold-out crowd at L.A.'s Kia Forum on Thursday for the FireAid wildfire benefit concert.

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

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.

The FireAid benefit concert on Jan. 30 aims to raise funds for Los Angeles wildfire relief efforts. With 28 artists, including Billie Eilish and the Red Hot Chili Peppers, all proceeds will be allocated to short-term and long-term relief initiatives,

"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"

A huge star line-up for a good cause: rock band Green Day and pop star Billie Eilish opened the FireAid benefit concert for those affected by the

St. Vincent performs with Krist Novoselic of Nirvana onstage during the FireAid Benefit Concert for California Fire Relief. (John Shearer/Getty Images for FireAid)

LOS ANGELES (Reuters) - 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 FireAid benefit concert will go down in history not only because it features some of the biggest names in music on the same stage, but for the message of hope those artists spread. And, hopefully,

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.