Actor Zac Efron has said he wants to play an ageing rock star so he can gain more than two stone in weight.

The Hollywood heartthrob said building his physique for the upcoming Baywatch film had taken “a lot of hard work” and he was unsure if he would maintain it.

Speaking at the premiere of his new film, Mike And Dave Need Wedding Dates, in Los Angeles, Zac said: “I would love to gain 30 pounds and play an ageing rock star. That would be an awesome transformation.

Zac Efron (Jordan Strauss/AP)
Zac Efron (Jordan Strauss/AP)

“I want to be honest with my characters. Otherwise, I’m just going to stay healthy fit.”

Zac, 28, has been sporting blond highlights in his hair for his role in Baywatch, the big screen adaptation of the classic 1990s television series.

His latest comedy is based on the true story of brothers Mike and Dave Stangle, whose bid to find dates for their cousin’s wedding by placing an online advert on Craigslist went viral in 2013.

It is the latest in a string of comedic roles for Zac, who found fame in Disney’s High School Musical films.

Zac’s co-star Alice Wetturlund said: “Honestly I’m amazed at his ability to do comedy. He approaches it as an actor so he’s very technical. He embodies the character perfectly.

“It’s mind-blowing, he’s so funny. I’m really excited at what he’s going to do.”

Anna Kendrick, Aubrey Plaza and Adam Devine also star in Mike And Dave Need Wedding Dates, which is released in the UK on August 10.