Katy Perry had the best day “catching up” with Taylor Swift backstage at the Eras Tour last year.

According to Glamour, the conflict began when three of Perry's backup dancers from her "California Dreams" tour joined Swift's "Red" tour but then left prematurely to join Perry on her "Prismatic" tour. This caused the feud to begin.

Dave Matthews and John Mayer (appearing together), Earth Wind & Fire, Gracie Abrams, Green Day, Gwen Stefani, Jelly Roll, Joni Mitchell, Katy Perry, Lady Gaga, Lil Baby, P!nk, Red Hot Chili ...

Follow live updates on the FireAid benefit concert, which will feature performances from Billie Eilish, Lady Gaga and more, as they raise money for Los Angeles-area wildfire victims.

Red Hot Chili Peppers were the last to take the stage at the Kia Forum at the FireAid benefit show for Los Angeles wildfire relief on Thursday night (Jan. 30), and the L.A. natives made sure to end the show on a high note.

The two-venue, FireAid Benefit Concert, was held in Los Angeles on Thursday night to help raise money for the Southern California communities affected by the devastating fires that ignited earlier this month.

A lineup of A-list artists is set to perform in the FireAid concert on Thursday, Jan. 30, benefiting the victims of the deadly Los Angeles wildfires . Billie Eilish, Olivia Rodrigo, Lady Gaga, Jelly Roll and Stevie Wonder are some of the mega stars slated to take the stage.

Follow live updates on the FireAid benefit concert, which will feature performances from Billie Eilish, Lady Gaga and more, as they raise money for Los Angeles-area wildfire victims.

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.

Here's where to watch FireAid L.A. benefit concert online, and how to stream performance Mayer, the Chili Peppers, and Billie Eilish free.

As Southern California begins to rebuild in the wake of the wildfires, Live Nation is assembling some of Hollywood's biggest talents in support.

Proceeds raised by the FireAid benefit concert will help those affected by the wildfires by raising money "for rebuilding communities devastated by wildfires and supporting efforts to prevent future fire disasters throughout Southern California," according to a press release.