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.

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.

The first of two concerts collectively being referred to as FireAid kicked off at the Kia Forum in the Los Angeles city of Inglewood, to support relief efforts in the wake of the deadly wildfires that ignited earlier this month in the LA area, claiming 29 lives and causing billions of dollars in damage.