“We used to dress up as ninjas and turn up at universities and gigs and play outside with a generator,” says Van McCann, lead vocalist, primary songwriter and guitarist for Catfish and the Bottlemen.

The British alternative rock quartet’s live setup will be considerably different for the next month and a half as McCann and his bandmates embark on a 24-city North American tour Tuesday, Aug. 1, as the support act on Green Day’s Revolution Radio Tour. They’ll play arenas, amphitheaters and even stadiums, including the Oakland Coliseum in the Rock and Roll Hall of Fame trio’s hometown of Oakland on Saturday, Aug. 5.

McCann has a sense of what a momentous occasion that concert will be for the East Bay natives. This summer, his group headlined the Echo Arena Liverpool, near where his father grew up and members of his family still live. “The show was about two weeks ago, and all my family just got home from their night out,” he says.

Audience size isn’t a concern for McCann, who founded Catfish and the Bottlemen in high school and named his band after a busker he met in Sydney when he was a child on vacation with his family. As is the case with many artists from overseas, Catfish and the Bottlemen are typically listed in the top few lines of music festival posters in the United Kingdom, Australia and Japan but are still playing clubs and theaters in the United States.

After writing songs in his bedroom and rehearsing for countless hours in various chilly spaces, the 24-year-old cherishes “playing in these massive places, and everyone’s singing the words back. But this Green Day tour will be different, of course, because nobody knows us,” he says.

When they played at BottleRock in Napa during Memorial Day weekend, they had a 5 p.m. slot on Friday. (“BottleRock was so good,” McCann says, marveling that Tom Petty and the Foo Fighters closed out subsequent nights.) And he recognizes that many patrons will be trying to park or may still be trickling in as his group performs its opening set.

“I always liked being a support band when we first started coming through,” he says. “Sometimes you’d be wedged in the middle of a five-band bill. And you’d always have to keep up the pace of the bands who played before you and then set the bar for the next two. So I liked warming up crowds.”

Green Day handpicked Catfish and the Bottlemen to be the opening act on the tour, McCann says. “How have we got on their radar? You bow down in respect to that.

“So we don’t mind if we’re playing to one person or 100,000. It’s the same show for us, because we’re buzzing to just be out of the house and doing what we’ve always wanted to do.”

Asked about his familiarity with Green Day, McCann says that he was reared on British hip-hop outfit the Streets (a.k.a. Mike Skinner). “So I like beats myself and me dance collection,” he says. But bassist Benji Blakeway and drummer Bob Hall have been “schooling” him in the dressing room on the band’s catalog.

Their sound engineer, in turn, already sports a large Green Day tattoo. “He’s going to have his shirt off every night,” McCann says.

Catfish and the Bottlemen are well positioned for large crowds and big spaces. Early songs such as the at times jittery “Tyrants” (found on the group’s debut album, “The Balcony”) and the more recent “7” (the leadoff single from follow up LP “The Ride,” released in late May 2016) play well in oversize settings in part because of a two-guitar attack fueled by lead guitarist/vocalist Johnny Bond.

Releasing a debut album seven years after first performing, McCann also had a chance to hone his considerable stage presence under a less intense spotlight before breaking out.

“Sometimes you hear people say, ‘Oh, this just happened overnight,’” he says. “But it was very much planned” — guerrilla ninja gigs and all.

Yoshi Kato is a freelance writer.

Catfish and the Bottlemen: Opening for Green Day. 7 p.m. Saturday, Aug. 5. $39.50-$79.50. Oakland Coliseum, 7000 Coliseum Way, Oakland. www.ticketmaster.com

Watch a clip of Catfish and the Bottlemen perform “7” live: https://youtu.be/Ibv5N70ncsk