Miley Cyrus’ covers of Pink Floyd and Led Zeppelin, Camila Cabello’s performances of brand new  singles “Liar” and “Shameless,” and several surprise collaborations were just a few highlights from the 2019 iHeartRadio Music Festival, which will air as a two-night television special on the CW tonight (Oct. 1) and tomorrow (Oct. 2) from 8 to 10 p.m.

The event, held on Sept. 20 and 21 at the T-Mobile Arena in Las Vegas, was hosted by Ryan Seacrest and also featured performances by Alicia Keys, Backstreet Boys, Cage The Elephant, Chance The Rapper, Def Leppard, French Montana, Halsey, Heart, H.E.R., Hootie & The Blowfish, Marshmello with Special Guest Kane Brown, Mumford & Sons, Steve Aoki with special guests Darren Criss and Monsta X, Tim McGraw, Zac Brown Band and more.

Seacrest and Christina Aguilera kicked off the show introducing Green Day, who burned through a set of hits that included “Holiday,” “Basket Case,” “Boulevard of Broken Dreams,” and their new single, “Father of All.” While performing the track, “American Idiot,” front man Billie Joe Armstrong switched the lyrics “I’m not part of a redneck agenda” with “I’m not a part of a MAGA agenda,” once again making their affiliation known.

Lil Nas X made a surprise appearance and brought “Old Town Road” to Vegas as part of his two-part T-Mobile Magenta Moment. Another treat for the audience came courtesy of Steve Aoki, along with special guests Monsta X, Backstreet Boys and Darren Criss. Criss captivated with a cover of The Dave Matthews Band’s “Crash Into Me,” and K-Pop cuties Monsta X joined Aoki for the collab, “Play It Cool.” Finally, The Backstreet Boys — returning to Vegas for an encore of their two-year residency for their own set — guested on the Aoki collab “Let It Be Me.”

Collaborations were once again a cornerstone of the night: Alicia Keys teamed with Lewis Capaldi for his single, “Someone You Loved,” and Marshmello and Kane Brown united for “One Thing Right.”

In a touching moment, McGraw paid tribute to the late Cars front man Ric Ocasek with a cover of “Drive,” while Hootie and The Blowfish got their funk on for Kool and The Gang’s “Get Down On It.”

Celebrities in attendance included Audrina Partridge, Dennis Quaid, Ian Ziering and Tori Spelling from Beverly Hills 90210, James Van Der Beek, Julianne Hough, Gavin DeGraw, Kennedy McMann and Scott Wolf from The CW’s “Nancy Drew,” Kevin Smith, Lucy Hale, Ashleigh Murray, Jonny Beauchamp and Julia Chan of The CW’s “Katy Keene,” Rachel Skarsten from The CW’s “Batwoman,” Scott Foley, Shawn Wayans, Taye Diggs from The CW’s “All American,” along with iHeartRadio’s on-air talent  Big Boy, Bobby Bones, The Breakfast Club, Woody, Tanya Rad and Sisanie.

Over the last nine years, $2 million have been raised and distributed to a number of charities including the American Association for Cancer Research, Ryan Seacrest Foundation, Musicians on Call, Augie’s Quest to Cure ALS, Lalela, The Genesis Foundation for Children, Community Foundation of NW Mississippi, City of Hope, Lupus Research Alliance, Camp Southern Ground, Kristen Ann Carr Fund and many more. Additionally, the Festival plays host to a number of critically ill children and their families through its long-term partnership with the Make-a-Wish Foundation.

See exclusive backstage photos in Variety‘s gallery.