Billie Joe Armstrong of Green Day surprises fans to promote their new film "Nimrods" held at Petco Park on July 24, 2026 in San Diego, California. Gilbert Flores/Variety

Green Day singer Billie Joe Armstrong gave fans the surprise of their lives on Friday (July 24) when the veteran pop-punk band’s leader jumped on top of an ice cream truck to play a surprise mini-set to promote the group’s upcoming coming-of-age rock road trip comedy Nimrods. Armstrong performed their Grammy-nominated 1994 single “Basket Case” in Gallagher Square outside Petco Park in San Diego, strumming an acoustic guitar while perched on the roof of a Mister Freezie’s ice cream truck, according to videos posted by fans.

Armstrong was later joined by bandmates drummer Tré Cool and bassist Mike Dirnt as they crammed into the truck emblazoned with the film’s title to hand out T-shirts, cassettes and ice cream to the thousands who’d gathered for the special event. In addition to the band — who are featured in the film that follows three teens as they speed from Kansas City to Los Angeles in the mistaken belief that they have scored a gig opening for Green Day — some of the movie’s stars were also on hand, including Jenna Fischer (The Office) and Mason Thames (The Black Phone) and director/writer Lee Kirk.

The movie follows the fictional group the Analog Dogs (Thames, Kylr Coffman and Ryan Foust) as they take a rowdy road trip across the country, believing that they’ve been tapped to open for their all-time favorite band on New Year’s Eve. The movie also co-stars The Office veteran Angela Kinsey, singer/actress Mckenna Grace (Paw Patrol: The Mighty Movie), SNL alum Fred Armisen, comedian Bobby Lee, Keen Ruffalo (Thor: Ragnarok) Ignacio Diaz-Silverio (A Good Person) and Sean Gunn (Guardians of the Galaxy).

Co-produced by Green Day, Nimrods originally premiered at the 2025 Toronto International Film Festival under its original title New Year’s Rev; the movie will open in the U.S. on Aug. 14. The accompanying soundtrack is due out on Friday (July 31) and features 22 Green Day classics, along with their new song, “I’m Never Gonna R.I.P,” four previously unreleased live tunes and tracks from The Paradox, Ultra Q and McKenna Grace, as well as four from fictional group Analog Dogs.

Get weekly rundowns straight to your inbox

Sign Up