Green Day opened the show with their song “Last Night on Earth,” featuring a surprise appearance by Billie Eilish, and then followed up with their anthem “Still Breathing”

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.