Tom Cruise didn't need to be coaxed to get into chaps and a glittery gargoyle codpiece for Rock of Ages. It was his idea.
Director Adam Shankman says he and Cruise found a picture of the lead singer of `80s band W.A.S.P. who was wearing a codpiece that shot flames out of it.
They both laughed about it and Shankman thought that was that, until he got a call from his costume designer.
"Tom wants a codpiece," Shankman remembers her saying.
"I was like, `OK'.
"She's like, `No, not just a normal codpiece, like a giant gargoyle head codpiece with a long red tongue'."
Cruise, who plays `80s rock god Stacee Jaxx in the movie based on the Broadway musical, didn't stop there.
At the costume fitting, Shankman saw Cruise in the chaps, and pulled the costume designer aside.
"I said, 'Are you going to put mesh back there or something?'," Shankman recalls.
But Cruise wouldn't have it.
It wasn't the only time the Rock of Ages cast and crew were surprised at the actor's commitment to playing the cashed-up, glamorous rock star.
"When we did the very first table reading, he showed up as Stacee Jaxx," co-star Mary J. Blige says.
"We're not even on the camera yet and he came with his entourage and his tassle jacket and his cowboy hat.
"Everybody was just looking in awe."
But Rock of Ages co-writer Justin Theroux (aka Jennifer Aniston's beau) wasn't surprised. He helped pen the screenplay for Tropic Thunder, in which an unrecognisable Cruise played the foul-mouthed, angry studio executive Les Grossman.
"He's really willing to go there and go out as far on a limb as you can write him, which is kudos to him because it's courageous to play such a broad, crazy (character)," he says.
Theroux says Jaxx was written to be a mash-up of rock stars such as Axl Rose, Steve Tyler and Jim Morrison.
"We were like, let's just make the craziest version of every single one of these guys," he says, which wasn't hard, seeing the movie is set in 1987.
"The decadence was so over-the-top. People who bought 400 snakes (or) have a car plated in gold and you just think, why?"
Shankman can attest to the fact that this lifestyle was all real.
The director says he "lived it" because his dad worked in the music business.
"I grew up on tour buses, I grew up in these rooms and my father was a manager, so I heard these stories," he says.
"There were no rules, so the behaviour - I mean, it was documented in the paper how insane everybody was.
"They taught Charlie Sheen how to be Charlie Sheen."
That rock star decadence is the backdrop for Rock of Ages' rock`n'roll love story between country girl Sherrie (Julianne Hough) and city guy Drew (Diego Boneta).
A jukebox musical, the movie features music from the likes of Def Leppard, Joan Jett, Journey, Bon Jovi, Pat Benatar and Twisted Sister.
Hough says the cast, which includes Alec Baldwin, Russell Brand and Catherine Zeta-Jones, immersed themselves in rock music before shooting.
"We went and did a little rock star college and we were there for six weeks and did vocal lessons and recording and guitar lessons and dance," she says.
The `80s-style set, which Hough says was built from scratch in Miami, also helped them get into character.
"It wasn't like we got off set and we were in a sound booth," she says.
"We were on the sunset strip that they built, so everybody was always dressed up like the `80s and it was fun."
Rock of Ages opens on June 14.