Just as FireAid hit the five-hour mark, Billie Eilish and her brother Finneas turned down the volume for an acoustic set as the night neared its end. Eilish had already made a cameo to set off the event earlier in the evening,

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

Billie Eilish and Finneas performed acoustic renditions of "Wildflower," "The Greatest," and "Birds of a Feather" at FireAid.

Highlights from the nearly six-hour Fire Aid included Lady Gaga, Billie Eilish, a female-fronted Nirvana reunion and an Anderson .Paak/Dr. Dre collab.

Two of the evening top-billed acts, Billie Eilish and Green Day, decided to sneak in an onstage duet. As the band geared up to play their beloved 21st Century Breakdown track “Last Night On Earth,” Eilish shocked viewers by picking up a microphone ahead of her set.

FireAid is a star-studded benefit concert organized for Los Angeles-area wildfire relief. It is being produced by Shelli, Irving, and the Azoff family with Live Nation and AEG Presents.

FireAid, featuring Billie Eilish, Lady Gaga, Sting, Red Hot Chili Peppers and others in a fundraiser for Los Angeles-area wildfire relief efforts, is the latest event to combine music and philanthropy.

P!nk, Joni Mitchell, and Lady Gaga were just a few of the highlights in a night that also featured a No Doubt reunion and the surviving Nirvana members

After joining Green Day for their FireAid-opening set at the Kia Forum earlier Thursday night (Jan. 30), Billie Eilish took the stage again at the neighboring Intuit Dome for the benefit concert, this time with her brother Finneas.

One of the great challenges faced by the events during Grammy Week, including the FireAid benefit, is how to set the proper tone: How do you have a celebratory event like big concert or awards show without seeming tone-deaf to the tragedy and loss so many suffered in the Los Angeles wildfires that ravaged the

"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"