Alec Baldwin on kissing Russell Brand in Rock of Ages: 'It was no Brokeback Mountain'

Tom Cruise's singing voice and could-be-spray-on abs aren't the only talking points around new movie musical Rock of Ages.

Alec Baldwin has opened up about being Russell Brand's sugar daddy on screen, and the "passionate kiss" they get to share.

"It's not like Brokeback Mountain, it's not two leading men who you are used to getting down with some gorgeous young girl," Alec told The Hollywood Reporter. "It's a little more chaste because I'm older (than Brand)."

The scene, which appeared in the original stage musical, involves club owner Dennis (Alec) and righthand man Lonny (Russell) confessing their love for one another singing REO Speedwagon's 'Can't Fight This Feeling', capped off with a smooch.

Alec, 54, said the moment was played for comedy and surprise, but resonates even more now after President Obama's recent endorsement of gay marriage.

"We live in an age, and I'm being imprecise here, where half the country gets it, and the other half doesn't. I live where men and women who want to get married — who gives a s---? No-one gives it a thought. It's like seeing women in power. Or like seeing African American CEOs," he said.

"We're in a fully realised age of equality in all things and it's not surprising or new. But there is that other half for whom that is surprising and new."

Russell, 37, confessed last week that kissing Alec, who he describes as a "good kisser" and "sexy man", was one of his career highlights.

"I certainly don't regret [kissing Alec]," he told reporters. "I'd do it again if there was a sequel — or even if there wasn't."