Some stars you never really look forward to interviewing, you know they're going to be difficult, uncommunicative, full of bullshit or just plain dull.
Others you want to spend the day with because they're natural, friendly, have no front and are just great company. The Rock falls firmly among the latter.
Born Dwayne Douglas Johnson in California, May 2 1972, when a shoulder injury put paid to a football career he followed his father and grandfather into the world of wrestling. First calling himself Flex Kavanah, then Rocky Maivia before finally adopting the name of The Rock, the WWE star made his move into feature films four years ago with The Mummy Returns.
So charismatic was he that a spin-off was rushed into production, elevating him to lead for 2002's The Scorpion King. That bowed at No 1, a feat repeated with Welcome To The Jungle. A year later Walking Tall made its debut at No 2.
It seems he can do no wrong. Even though Be Cool attracted scathing reviews, Johnson emerged smelling of roses for his comedic turn as a gay bodyguard cum wannabe country singer. This month, now billed as Dwayne 'The Rock' Johnson ("it's happened naturally and over time I think 'The Rock' will fade away, it's just a nickname") he notched up his third No 1 opener with Doom, the feature adaptation of the world's most popular - and most violent - computer game.
Already a fan, when he was approached to join the film project Johnson had little hesitation about getting on board.
"I loved Alien and The Thing, but I've never been part of the genre and I really wanted to make a good sci-fi horror movie," he admits.
"What I liked about those films and what we brought to Doom was the atmosphere of tension in which you hear things but don't necessarily see the monster."
It was, he says, also important to stay true to the game.
"Doom started 15 years ago and Doom 3 broke all records when it came out last year. Why screw with that? I spent a lot of time with the creators in Texas because I wanted to make sure I understood its geography and that the script and their thoughts meshed together.
The game is very unapologetic in its approach and so is the movie and I think Doom fans will appreciate that. But even if Doom wasn't a game, it would still be a good sci-fi horror!".
Refreshingly though, The Rock's not someone who tries to persuade you that it's really all about the subtext.
"I'm not going to sit here and talk about the incredible arc of my character," he laughs.
"I make no bones about Doom, it's a soda popcorn movie. But I get transported to Mars, there's the biggest gun in the history of movies and I get to shoot monsters. It's awesome."
Interestingly, he was originally approached to play Reaper, the film's brooding hero. Instead, he opted for the role of Sarge, the leader of the Special Forces Unit. And not just because that's who gets to fire the BFG!
"Reaper was an interesting role, but I'm more intrigued by Sarge. There were more layers I could play with as an actor. This is a guy trying to hold everything together but he's faced with the daunting task of dealing with monsters. In warfare you have to think like that (snaps his fingers) and if it means getting rid of one of your own for the betterment of the group, then so be it. Heroes save the world, I thought it would be more interesting if I was trying to end it this time around!"
Interesting but, he confesses, also incredibly hard work.
"To be totally honest, Doom was the most difficult movie I've done, physically and mentally. We filmed in Prague and I never saw the sun. I woke up at 4.30am to go to the soundstage and we wouldn't get out until seven. And it's not some light comedy.
"Every day there's blood and death. We hired real amputees for some scenes, and between make-up and prosthetics, it looked like their arms had literally been ripped off. So it was tough and intense. I had to keep reminding myself that making movies is fun!"
Audiences may agree it's the best computer game adaptation yet, but, having previously passed on making The Pacifier, it's certainly another film four year old daughter Simone isn't going to be watching daddy in. That, he reveals, is something he's about to put to rights.
"Universal edited down The Scorpion King to scenes she could watch, so basically that was me riding a camel, and then me riding a camel again, but I'm happy to say I'm making a tug on your heart comedy for Disney called Daddy's Girl I play the NFL's best quarterback. I'm very brash but not to the point of being unlikeable. But then my life gets flipped upside down when I learn I have a daughter."
Prior to that, Johnson's got a decidedly full schedule, taking the title role in Johnny Bravo, starring in John Woo's Spy-Hunter, playing opposite Pierce Brosnan in fantasy adventure Instant Karma, and as Ryan Reynold's cop brother for action comedy Blowback.
First up though are two decidedly contrasting outings.
Based on a true story, in Gridiron Gang he plays a correctional facility counsellor who forms a football team of young criminals while Southland Tales is an art house science fiction dark comedy cum musical from Donnie Darko writer-director Richard Kelly.
"As you can imagine," he laughs, "there are many interpretations of the script. I play a movie star with amnesia so I don't know I'm a movie star. I'm extremely neurotic. I'm a paranoid schizophrenic, and I can foresee the future and the end of the world coming."
He breaks into a big grin. "And it gets better! Sarah Michelle Gellar is my porn star girlfriend and Mandy Moore is a senator's daughter who is my wife."
With far too many actors who, as he puts it, forget that making movies is a privilege and take themselves too seriously, it's always a pleasure to talk to Johnson, who says that "at the end of the day, we're not building rockets" but, while able to laugh at himself, never gives less than 100 per cent to his work and his fans.
"My mom told me always go for broke," he says. "I would rather strike out rather than never have stepped up to the plate."
