Sly's brawn to be mild

As I enter his penthouse, I find Sylvester Stallone in mid-fight - though this time it's verbal. 'I used "derring-do"?!' he guffaws incredulously at his publicist. 'Bulls**t! I would never say "derring-do".' Although, as he admits to me with a charmingly goofy chuckle: 'I'm very hung up on archaisms...'

At 61, it's no surprise to find that the globe's most recognisable action hero is increasingly hung up on past glories: the very reason I'm here is because (incredibly) he's back on our screens for the fourth Rambo movie. No, what's really surprising is that, for a man whose best-known films cast him as a monosyllabic meathead and is these days as much joke as icon, he uses words like 'archaisms' at all.

As Stallone lolls casually back on the sofa, his absurdly bulging biceps making a freakish, Alien-like bid to burst out of his arms, I am knocked out by his articulateness, particularly when he expounds upon how 'the character of Rambo harks back to the mythic one man who has been chosen to do a job that he really doesn't want to do, but has no other recourse'. What's with this love for romantic language?

'I feel a lot of people don't understand me,' sighs Stallone. 'We are always so hung up on physicality. If I had glasses, smoked a pipe and was losing my hair, maybe they'd say: "Oh, what a bright guy." Sure, I've done some films I'm not proud of' - a gracious understatement given Stallone was awarded the Golden Raspberry award in 2000 for Worst Actor Of The Century - 'but I learned early on that a character like Rambo, the more he talks, the less interesting he is.

'I wrote some speeches that really explain who he is and why he's there - and then I realised it's diminishing. I don't want him feeling sorry for himself. Some people think the more they talk, that's what acting is. It's much harder to say less.'

Saying less is arguably what Stallone does best. He is risible and cartoonishly overblown as Vietnam vet John Rambo, this time on a mission in Burma ('Liar!' he bellows good-naturedly when I politely say I liked the new movie). But the brooding, melancholic, psychologically damaged core he gives to the character holds a glimmer of the quality that led revered critic Roger Ebert to prematurely herald him as the next Marlon Brando following his role in the Oscar-winning Rocky.

Meeting him in the flesh, Sly's more like Tweety Pie than Brando: short with twig-like legs and puffed-up torso, grotesquely misshapen by years of over-exercise. It's hard to take him seriously, particularly when we discuss his favourite hobby, oil painting (no, really), and he earnestly tells me: 'I always say to people: "Don't put me in the same bracket as Picasso."' Like that was a danger...

If it's all too easy for us to underrate Sly, maybe it's because he's already done that himself. Despite his millions, a decision to pump up the bank account and body over the acting muscles have led to a string of turkeys and now a comfort-blanket return to the roles that made his name.

'Rambo is going to be very hard for me to let go of because I love the character,' he says. 'I think he represents an incredible kind of bitterness and discontent and the heartbreaking realisation that you don't always get out of life what you put into it. Life is unfair. You put your blood into it and guess what? You're still unhappy.'

That rage and sadness is presumably what led 15-year-old Stallone to be voted 'most likely to end up in the electric chair' by his classmates and, most recently, to identify himself with Edgar Allan Poe, the tormented Gothic writer whose bioflick is Stallone's next writer/director project.

'He had all these nightmares and he said: "OK, how do I deal with these? I can kill myself or I can write about it,"' he says. Rambo, of course, just kills everyone else: at one point in the new film we see him slowly ripping out a man's throat with his bare hands. 'It's not gratuitous,' Sly insists. 'The man's a rapist. I deliberately prolonged it.