Travis Barker and Machine Gun Kelly Join Avril Lavigne Onstage for L.A. Concert

Megan Fox and Kourtney Kardashian were also at the event.

Travis Barker and Machine Gun Kelly took the stage with Avril Lavigne, and things got bubbly!

Barker, Kelly and Lavigne hit up the famed Roxy Theater in West Hollywood on Friday night for SiriusXM and Pandora's Small Stage concert series. Once onstage, Kelly and Lavigne proceeded to pop a bottle of champagne. After all, there was plenty of reason to celebrate, as the event coincided with the release of Lavigne's first album in three years, Luv Sux.

Kelly and Barker performed alongside Lavigne for their "Bois Lie" track. And, it was the first time Kelly and Lavigne performed the track together onstage. Barker joined Lavigne for four tracks, with the Blink-182 drummer also performing for a special spectator in the crowd, his fiancée Kourtney Kardashian.

And, yes, for good measure, Kelly's fiancée Megan Fox was also in the crowd. Lavigne also performed her hit single "Bite Me" and "Love It When You Hate Me," among others.

Barker and Kelly were far from the only special guests who joined Lavigne. Her boyfriend Mod Sun also took the stage with her. Some other celebrities in attendance included Willow Smith, Tyler Posey and Huddy.

Machine Gun Kelly, Travis Barker and Avril Lavigne perform onstage at the Roxy in West Hollywood. (Emma McIntyre/Getty Images for SiriusXM)
(Photo by Emma McIntyre/Getty Images for SiriusXM) - Getty
(Photo by Emma McIntyre/Getty Images for SiriusXM)
(Photo by Emma McIntyre/Getty Images for SiriusXM)

ET's Lauren Zima spoke to Lavigne earlier this week, revealing she had, in fact, met Fox following her collaboration with Kelly. Lavigne's impression? "She's really lovely!"

Lavigne also told ET what it was like to collaborate with Barker again. He previously worked with her on her 2007 album The Best Damn Thing.

"Making the album with Travis has been a lot of fun because we worked together 15 years ago... and then we reconnected with this record and he's evolved so much," she shared. "He's gone from being an artist in a band to, you know, having a record label, producing and writing, and it's been so much fun."

Ditto with Kelly.

"It was really great to see him working in person and to experience that," she said of the rocker. "He plays guitar and he's a really amazing songwriter and he brought in an idea for me and we wrote it together and we recorded and it was like so chill."