Billie Eilish, Lady Gaga and Nirvana reunion: The biggest moments from FireAid

It was a night of electrifying performances and emotional moments as the world of music came together to honour those affected by the devastating California wildfires.

More than 20 artists took to the stage for the epic five-hour show, held simultaneously at two large venues in the city: the Kia Forum and the Intuit Dome. The online stream switched between the two arenas throughout the night.

Green Day kicked off the monumental show at the Kia Forum with a rendition of 'Last Night on Earth' and were soon joined by Billie Eilish for the first surprise of the night. After their set, Green Day frontman Billie Joe Armstrong hugged actor Billy Crystal, who was there to welcome the crowd at the Kia Forum.

“Our goal is simple tonight, to spend more money than the Dodgers spent on free agents,” he joked. He told the audience U2 offered the first big donation of the night: $1million.

Crystal said he was wearing the clothes he had on when he evacuated. He lost his home in the in the Pacific Palisades neighbourhood that he lived in for 46 years.

“Janice and I lived in our home since 1979. We raised our children and grandchildren here. Every inch of our house was filled with love. Beautiful memories that can’t be taken away. We are heartbroken of course but with the love of our children and friends we will get through this,” the Crystals wrote in a statement early this month.

California served as a central theme throughout the night: The Red Hot Chili Peppers rocked hits like 'Dani California' and 'Californication', while Dr. Dre delivered an unforgettable performance of 'Still D.R.E.' alongside Anderson .Paak and Sheila E. before transitioning into 'California Love'.

Laurel Canyon folk legend Joni Mitchell graced the stage with a poignant rendition of 'Both Sides Now', all while sitting on a gold throne.

Katy Perry performed a euphoric set, beginning with 'Rise' alongside the Pasadena Chorale, followed by 'Roar' and 'California Gurls'. Eilish and her brother Finneas, who've called Los Angeles home for their entire lives, performed beautiful acoustic versions of her recent hits 'Wildflower', 'The Greatest' and 'Birds of a Feather'.

Behind the early performances, moving images of firefighters and the devastation caused by the fires were displayed on the big screen. And throughout the event, viewers and attendees were encouraged to donate to the cause via FireAidLA.org.

In perhaps the biggest surprise of the night, the remaining members of 90s rock band Nirvana - Dave Grohl, Pat Smear, and Krist Novoselic - reunited with a lineup of guest female vocalists stepping in for the late Kurt Cobain, including St. Vincent, and Kim Gordon of Sonic Youth. Together, they performed iconic tracks like 'Breed' and 'Territorial Pissings'.

Elsewhere, Olivia Rodrigo, Stevie Wonder, Sting, Pink, Fleetwood Mac singer Stevie Nicks, and Earth Wind & Fire also delivered memorable performances.

Closing the night, Lady Gaga powered through the Oscar-award winning 'Shallow' and 'Always Remember Us This Way' from A Star Is Born, before playing a new song on the piano.

“It’s just for tonight, it’s just for you,” she said of the song she wrote with fiancé businessman Michael Polansky. “All I need is time,” she sang in the folk-y pop chorus. “To heal my broken wings and then I'll soar.”

At least 29 lives were lost, and more than 16,000 homes and businesses were destroyed in the fast-moving, destructive fires that erupted in early January. Proceeds from the concert, along with donations made throughout the event, will support the rebuilding of communities and efforts to prevent future fires in the region.