The Offspring frontman Dexter Holland ditches his guitar for a wetsuit as he takes part in Sydney triathlon

The iconic US singer shook off all punk rock stereotypes when he shocked crowds in Sydney.

The lead singer of iconic US rock band The Offspring has been spotted in Sydney, looking a world away from his rock star onstage persona.

The band had a day off in Sydney on their tour of the country last week and instead of the usual rock star antics, frontman Dexter Holland grabbed his wetsuit and headed to the nearest triathlon.

The Offspring frontman is in Sydney doing a triathlon. Picture: Instagram.

The rocker looked far from his usual rocker stage persona. Picture: Instagram.

“If you wanna look cool, just dress up for a triathlon,” he told his followers in a video he shared on the band’s Instagram account.

Holland took part in the Penrith triathlon last weekend, enduring a 750-metre swim, a 20-kilometre bike course, and a 5-kilometre run. The rocker took part in the strenuous event with his assistant, and his bandmates turned up later, vodka in hand, to support him to the finish line.

PTC Club President Mark Thomas told the Western Weekender: “They kept it under wraps a bit, so it was rather surreal for the volunteers when he checked in.

“Dexter is training for an upcoming 70.3 event, and even though he is on tour, his coach is still sending him training programs to adhere to. It just so happened, our local club race coincided with them being in town, and his training schedule.”

The Offspring just finished up their sellout tour of Australia. Picture: Daveed Benito / Supplied.

The Offspring finished up their tour of Australia earlier this week with their final show in Brisbane.

The Offspring first emerged out of California in the ’80s, and eventually rose to become one of punk rock’s most enduring bands.

They celebrated a rare achievement for legacy rockers twice this year when they reached the one billion streams milestone on Spotify, pointing at a wave of new young fans.

Lead guitarist Kevin ‘Noodles’ Wasserman recently revealed that the band loves to tour Down Under.

“It’s such a fun vibe; we love coming,” he told Beat. “You guys have a wicked sense of humour. You love to take the piss. Plus, tons of energy. It feels similar to the US, only funnier and maybe a little smarter.”

The rockers were supported by fellow 2000s legends Simple Plan on their tour of Australia, which featured numerous sold-out dates.

Speaking of their fellow rockers, Noodles said that they’re “super nice guys.

“They’re poppy punk, but when you see them play live, those guys rock,” he insisted.

Originally published as The Offspring frontman Dexter Holland ditches his guitar for a wetsuit as he takes part in Sydney triathlon