Cody Simpson is back performing in Guys & Dolls – and says ...

Australian pop star and former competitive swimmer Cody Simpson is returning to performing — and believes swimming has helped make him a better singer.

Simpson, 27, has just announced he'll be making his Australian theatre debut next year — in Opera Australia's new production of Guys & Dolls on Sydney Harbour.

"I can't wait," Simpson told ABC News Breakfast. "There's been a lot of joking about because the stage is on the water. I can't seem to get away from the water. Even when I'm performing."

Cody Simpson will play Sky Masterson in Guys and Dolls alongside Jason Arrow as Nicely-Nicely Johnson and Bobby Fox as Nathan Detroit. (Supplied: Opera Australia)

Discovered on YouTube, Simpson shot to fame in 2010 after releasing his debut single, 'iYiYi'. At one point touted as the "next Justin Bieber", he went on to release four solo studio albums before announcing a shock return to competitive swimming — a sport he loved and found success in when he was younger.

He joined the Australian Swim Team in 2022 after qualifying for the Commonwealth Games in Birmingham, where he won gold in the 4x100-metre freestyle relay and silver in the 4x100-metre medley relay.

Cody Simpson announced his retirement from swimming in early 2024. (AAP: Darren England)

But after narrowly missing out on qualifying for the Olympics, Simpson announced his retirement from swimming earlier this year.

"To have been able to swim for Australia in that time is unbelievable. It's like a box ticked off for my life.

"I don't have to live with those 'what ifs' or regrets as an old man anymore, and I can go back into doing this stuff without any sort of lingering itch."

In Guys & Dolls, Simpson will be playing the lead role of Sky Masterson — a character made famous by Marlon Brando in the classic 1955 film, which also starred Frank Sinatra.

Sinatra famously developed his vocal technique by holding his breath underwater for long periods of time in his pool — something Simpson found useful in returning to singing.

Rehearsals for Guys & Dolls begin in early 2025 but Simpson says he already knows most of the songs. (Supplied: Opera Australia)

"That's something that I researched and read about," Simpson says. "He used to swim laps, do breath holds.

"We used to do a lot of that stuff in my training, like a lot of hypoxic stuff, and I actually found that coming back into singing, I almost had a better capacity and strength even though I hadn't sung for the better part of four years.

"Coming back into it, I had all that lung training."

Annie Aitken will also star in the production as Sarah Brown. (Supplied: Opera Australia)

Landing the role in Guys & Dolls was a dream come true for Simpson — who says the show helped spark his love of musical theatre as a teenager.

"It was always my aim to do more of it once I retired from the pool and I was able to jump right back in.

"Fortunately I already knew most of the songs even coming into my audition which was awesome. I didn't have to learn the songs as much as I had to learn the scene, the script and start to embody the character of Sky.

"Acting is all about getting to live out your fantasies onstage, right? It's just going to be an unreal kind of vibe and energy to bring to Sydney."

The Handa Opera on Sydney Harbour production of Guys & Dolls will play from March 21 to April 20, 2025.