Matt Damon: "Ben Affleck is my hetero lifemate"

Matt Damon has talked about the enduring nature of his friendship with his "hetero lifemate", Ben Affleck.

It was, he admits, painful to see Affleck's career destroyed by gossip magazines when he was dating Jennifer Lopez between 2002 and 2004. "I would talk to Ben during that time and he'd go: 'I'm in the absolute worst place you could be – I can sell magazines, but not movie tickets. It is jail. I'm totally fucked right now.'"

Although he is delighted by Affleck's recent success with the Oscar-winning 'Argo', Damon recalls a time when his friend was desperate to escape the world media.

"Our agent, Patrick, called the editor of 'US Weekly' and begged her to take him off the cover. He said: 'I promise you there's nobody in New York or LA who wants to see Ben on the cover of a magazine any more.' And she goes: 'You're right, but it's not my fault that everyone between those cities does still.' And they literally kept him on the cover until every single person in America was like: 'I can't stand this guy.' And that was 10 years ago. It took him 10 years of really hard work to climb back up the mountain."

After years of living in New York, Damon has just bought a house down the street from Affleck in Los Angeles. He says they are working on a few projects together through their production company Pearl Street Films, the most advanced of which is a biopic of James "Whitey" Bulger, a vicious Mob boss from Boston known locally for his Robin Hood acts of philanthropy. Damon is set to play Bulger and Affleck will direct.

Affleck may have spectacularly turned his career around, but Damon notes that there is a still a handful of paparazzi stationed day and night outside Affleck's house, where he lives with his wife, Jennifer Garner. "A lot of it boils down to luck: my wife's a civilian and that takes a lot of pressure off," says Damon, who previously dated Minnie Driver and Winona Ryder. "It's really sex and scandal that moves those magazines, and there's nothing scandalous about a guy who's married and has kids. If they come outside where I live, they are going to die of boredom – there's just nothing really going on that would sell a magazine."

The 42-year-old actor was speaking in an interview with 'The Observer' about his new movie, the fracking drama,  'Promised Land' - the first proper full-length script that Damon has completed since 'Good Will Hunting'.

Damon co-wrote the script with John Krasinski, an actor who starred in the long-running American edition of 'The Office' (and is married to Emily Blunt).

Krasinski would show up at Damon's house at 8am each Saturday and they would write all weekend, only breaking for meals and screenings of 'The Little Mermaid' with Damon's kids.

Damon met his wife, an Argentinian-born bartender called Luciana Bozán, while he was shooting the comedy 'Stuck on You' in Miami in 2003. Luciana – whom Damon calls Lucy – already had a six-year-old daughter, Alexia, and they have since had three girls together: Isabella, Gia and Stella.

Damon's advice on living in a household of five women is simple: "Find yourself a little man area."

Damon doesn't smoke any more.  "Ben and I started when we were in high school. We'd see the great actors – Brando, James Dean, Mickey Rourke, who we loved back then – smoking, and we just thought it was fucking cool."

So what made him stop? "Life," he says. "Actually, I remember my brother gave up before he had kids and he said: 'I'm going to give myself six months or a year to clear out my system before I, you know…'" Damon suddenly becomes a little coy. "Whether there's any wisdom to your sperm-carrying, your system being somehow cleaner, but that was his thing and I remember thinking: 'Yeah, I'll do that, too.' Lucy and I knew we'd be having more kids and that process started a year later."

He has recently completed a biopic of Liberace called 'Behind the Candelabra' co-starring Michael Douglas as Liberace.

The film was turned down by every major US movie studio for being, in Soderbergh's words, "too gay".

Eventually the $5m budget was covered by the cable channel HBO, and it will be aired in the States next month.

Damon admits the film will not appeal to everyone – "They can change the channel" – and that it was a stretch, at least initially, for him to play a part that involved nakedness and passionate clinches with Michael Douglas.

"What really helped was the clothes and the hair," he says, smiling. "I had four different wigs and these phenomenal outfits, and they really helped the way that I stood and the way I walked. It was like osmosis; I totally got into it."

'Promised Land' is out on 19 April