An absolute highlight of FireAid was the comet-like reappearance of the remaining members of Nirvana onstage together playing the band's songs again.

Surviving Nirvana members Dave Grohl and Krist Novoselic and former touring guitarist Pat Smear reunited at the California wildfires benefit concert FireAid on Thursday night. They played four Nirvana classics with the help of some guest vocalists.

FireAid, a sprawling benefit concert for wildfire relief, featured Joni Mitchell, Stevie Wonder, Billie Eilish, Lady Gaga, members of Nirvana and dozens more.

The surviving members of Nirvana — drummer Dave Grohl and bassist Krist Novoselic, as well as touring guitarist Pat Smear — reunited for the first time in five years at the FireAid benefit concert.

But for Violet Grohl taking the place of Lorde, it was the same group of singer/guitarists the remaining Nirvana trio played with at their Rock and Roll Hall of Fame induction performance in 2014

Dave Grohl, Krist Novoselic and Pat Smear reunited and were helped by variety of guest vocalists for a Nirvana performance at the FireAid benefit concert.

A rotating group of women vocalists joined the surviving members of the legendary '90s band for a raucous reunion set.

Nirvana brought out St. Vincent, Kim Gordon, Joan Jett, and Violet Grohl during a surprise reunion set at FireAid.

A trio of singers filled in for Kurt Cobain as Dave Grohl, Pat Smear and Krist Novoselic performed "Breed," "School" and "Territorial Pissings.”

Pop stars, rock legends, first-responders and wildfire survivors came together for FireAid, a star-studded, two-venue benefit concert that stretched into the early-morning hours Friday to raise money for those affected by the recent wildfires.

From surprise guests to touching moments of humility, here were the most memorable moments from the Jan. 30 FireAid benefit concerts in Los Angeles.