Sexiest man alive Ryan Reynolds dons his CG tights for Green Lantern

Ryan Reynolds has two small, single-colour tattoos on his lower left arm. One is a series of words engraved into the tender part of his wrist, the other some kind of military gun. I ask about them and his right hand moves quickly and instinctively to cover his left arm. He forces a laugh. “Oh, it says, ‘You’ll regret this one day, you idiot.'” And do you? He shrugs: “Yes.”

Reynolds doesn’t particularly appreciate questions that creep into his personal life, although when I later find out that the words simply say “Know Thyself” and that the gun is in fact an old naval cannon, I wonder if he’s being slightly sensitive. Anyway, it’s clear that the personal is private: his assistant has already issued a friendly warning that there are to be no questions about Scarlett Johansson, to whom Reynolds was married for two years until last December. I assume that also means no questions about singer Alanis Morissette, a fellow Canadian – Reynolds was born in Vancouver 34 years ago – to whom he was engaged before meeting Johansson. Which is fair enough, really, but it does mean that Reynolds spends the first 25 minutes of the interview positioning his 6ft 2in frame right on the edge of the sofa just in case I recklessly decide to breach protocol.

So we talk instead about green tights and magic rings. Over in the States, Reynolds is a big deal and he’s about to go properly global with the adaptation of DC Comics‘ 71-year-old Green Lantern story. He plays Hal Jordan, a test pilot with commitment issues who is the first human inducted into an intergalactic group of peace-loving superheroes who go by the name of the Green Lantern Corps. Hal must save the Earth and the universe – and get the girl – but only if he learns to overcome fear with willpower. A lighthearted hero, Reynolds anchors the film but doesn’t carry it; it’s more an ensemble piece, with Peter Sarsgaard as the nerdy scientist infected by alien matter and Mark Strong as Sinestro, a sardonic Green Lantern leader and baddie-in-waiting.

‘Changing body shape is part of your job … A few months later you’re back on the couch watching daytime TV’

It’s always entertaining to watch a mere mortal unlock their exceptional potential in a superhero story. But with the Iron Man, X-Men and Batman franchises all active, as well as the much-anticipated Avengers film on the way, does anyone apart from the most devoted fanboy really care about another comic-book adaptation? Reynolds raises an eyebrow and laughs: “I don’t think Green Lantern will be a hard sell at all. It differentiates itself from other comic-book films because it doesn’t have the darkness those typical superhero stories have in terms of their backstory. It’s just a fun, epic summer movie that is not too precious about anything. I loved watching Harrison Ford as Han Solo in Star Wars when I was a kid. I tried to learn from him – he often rolled his eyes at something ridiculous that was happening in front of him. So I’d say what also distinguishes Green Lantern is its ability to laugh at itself.”

Reynolds says he has always been good at self-mockery: “I laugh at myself more than anything else.” This, he explains, goes back to his days in an improv comedy group at school in Vancouver. He may have failed drama class at the age of 12 but by 14 he had moved to Florida and was making his television debut in the Nickelodeon show Fifteen. Throughout the 90s Reynolds appeared in made-for-TV movies and television series such as Sabrina The Teenage Witch before, in 1998, securing a role in Two Guys And A Girl.

In the past decade he has become known as the buff, handsome actor able to genre-jump: he has done comedies (Just Friends, Van Wilder: Party Liaison), horror (The Amityville Horror remake, which is memorable to his fans mostly because it featured Reynolds chopping wood topless), action thrillers (Blade: Trinity) and, in 2009, his breakout romcom The Proposal, in which he starred opposite Sandra Bullock. Yet he doesn’t only go for big-budget, glossy movies; last year he was in Buried as a civilian truck driver kidnapped in Iraq and buried alive. An even better example of his indie credentials is the relatively low-budget 2007 film The Nines, in which Reynolds played several characters. Variety declared him “sensational”.

John August, who directed The Nines, has called Reynolds the Facebook generation’s actor – becoming “a star through aggregation”; other directors talk of his lack of vanity and work ethic. He certainly gave Green Lantern everything, doing as many of his own stunts as he could and ending up with a separated shoulder and in need of two minor operations. Wearing a grey motion-capture unitard (the green suit is all CG), he sweated his way through 104 days (his estimate) of 100-degree New Orleans heat. Every day he would observe a rigorous exercise regime. “For the most part it was the usual gruelling mess of early morning squat thrusts and crap like that.” Did his body go to pot as soon as he stopped training? “It doesn’t so much go to pot … I just kind of shrink.”

‘When I arrived in LA, Jason Bateman was the first person to be nice to me. And you’ll always remember that guy’

The sleeves of his grey shirt are rolled up to the elbows and his biceps appear to be on the verge of ripping through, but his waist is surprisingly narrow and he’s certainly no incredible hunk. “Changing body shape is part of your job and it’s not something I bemoan. I keep thinking, this too shall pass, and it does. A few months later you’re back on the couch watching daytime TV.”

It’s quite hard to imagine Reynolds lounging around on the sofa aimlessly watching TV: he’s widely read (Philip Roth is a favourite), he’s contributed a series of well-written and often funny blogs to the Huffington Post and he likes to work. He’s just finished Safe House, a CIA thriller starring Denzel Washington and Vera Farmiga and filmed in Cape Town. I heard that Reynolds cried 26 times in one day for a particular scene. How did he do it? I feel the glare of the publicist behind me, but Reynolds smiles: “To really let go like that 26 times in a row was tough. Sometimes the job is absurd and you just have to get through it.”

Currently, Reynolds is saving the world in green tights and in August he will return in a comedy with his old friend Jason Bateman. Written by the Hangover team and directed by David Dobkin of Wedding Crashers fame, The Change-Up looks, from its trailer, to be daft and funny. Reynolds calls the story – in which he and Bateman switch bodies – “the most impossibly stupid premise” and “absurd in a grounded way”. How did he and Bateman meet? “When I first arrived in Los Angeles 14 years ago, he was the first person to be nice to me. And you’ll always remember that guy!”

But Green Lantern and The Change-Up guarantee Reynolds the kind of celebrity he is not sure he really wants. He’s glad he only really got famous a few years ago, with The Proposal and his marriage to Johansson, because he’s not sure he could have handled it in his 20s.

I am given the last question signal. It’s embarrassing to have to ask this, I start to say, and the air seems to be sucked out of the room. What does it feel like to be the Sexiest Man Alive, as voted for by People magazine last year? There is a collective sigh of relief; the divorce has not been mentioned. Reynolds sits back on the sofa and slaps his thigh: “Oh God! Yeah! I feel like it was designed to give my three older brothers ammunition to destroy me on a routine basis.” He narrows his eyes, which are just a tiny bit too close together. “But seriously? That stuff is just silly.”