Jack Black has nothing against the slacker humour that has made him a comic star, but he's not averse to playing more thoughtful comedy and even romcom - as long as it's cool. So put Jack in a box at your peril, writes Brian Boyd.

'I AM a humble and sensitive person" says Jack Black with a serious, almost wounded, look on his face. "And I'm a very humble and sensitive actor, which may surprise some people but it's actually true. I'm not stupid. I know what my reputation is, but I decided a long time ago not to be funny all the time. I can be the funny slacker dude if you want, but I can be other things besides."

Jack Black is in a London hotel room talking about "other people's perceptions" and how they have both helped and hindered his film career. He talks about flexing his dramatic role muscles with some intensity until, just for a laugh, you remind him about the film you are her to discuss.

Be Kind Rewind stars Black as a funny slacker dude who believes the power plant next to his house is melting his brain. Attempting to reverse the damage, he gets caught up in an electromagnetic field which leaves him magnetised.

From such a précis, you would expect the film in question to be a Frat Pack romp, with lashings of gurnings and pratfalls. But Be Kind Rewind is actually a thoughtful, lo-fi comedy with a whiff of the art-house about it. It's also a "message" film that, despite its feel-good ending, does raise such issues as DIY media creativity and the sometimes absurd nature of copyright law.

Black's best friend in the film, played by Mos Def, works in one of the last videocassette-only rental shops in the US. As a result of his newly magnetised state, Black erases all the tapes in the shop. This is disastrous for the shop's most loyal customer, a sweet old lady (Mia Farrow). So, to cover up, Black and Def go out onto the streets and recreate, YouTube-style, all the films that she wants to rent out.

"The role was great for me," says Black, "because, when I was a kid, I used to do something similar. I used to pretend to be making episodes of The Six Million Dollar Man with me as Lee Majors. So getting the chance to make all those famous Hollywood films was a joy for me.

"We did Superman but you'll have to take that name out because we had to change the name in the film to something like Incredible Flying Man. We did Driving Miss Daisy and I played Jessica Tandy. We did King Kong. But our absolute masterpiece was Ghostbusters, even if while we were filming it myself and Mos sort of swapped characters accidentally. Recreating RoboCop was great as well. A lot of the films we wanted to do we just couldn't get clearance on, such as Back to the Future.

The sweet old lady in the film is none the wiser about the provenance of the videos she rents. But, to explain the delay in supplying her with the films (and their increased rental cost), Black and Def tell her that they have to be imported from Sweden.

"Because of this we come up with the word 'sweding'. Sweding is central to the film; what it means is taking something old, putting your own spin on it and getting something new. So the Ghostbusters that is rented out is a different creation to the real film but still contains the most important elements of the original. It's like we have done our own YouTube remake of the film". Sweding is also central to how Be Kind Rewind is being marketed (see panel).

The film is directed by Michel Gondry, who is best known for Eternal Sunshine of the Spotless Mind. Black says Gondry was critical in transforming Be Kind from hi-jinks farce into something a bit more thoughtful.

"Michel Gondry has a very interesting way of shooting scenes. He didn't have that big-budget comedy thing of covering a scene from all the different angles. And the plot and story weren't that important to him as long as he had an amazing visual image. He really brought a DIY vibe to proceedings just as the characters do in the film. He actually designed and handmade all the props and costumes we used when sweding the films. And he has a nice, spontaneous approach.

"I've worked with some directors - I won't mention any names - who have a very fixed idea of what they want you to do. I'm a more 'alarm-clock'-style actor, so having it all planned out for me doesn't really work. The whole style of this film meant that I could react to the, at times, chaos around me."

Gondry really had only one golden rule, says Black: the actors were forbidden from researching the films they had to recreate. "If we had seen it, we were to try and not remember it; if we hadn't seen it, we weren't allowed watch a copy of it. The idea was to put us in the same situation as the characters who were under pressure to recreate these works. There was never any sense of us going for a good approximation of the real film."

With its engaging, lo-fi warmth, Be Kind Rewind will probably be filed beside School of Rock, High Fidelity and Nacho Libre in the Black canon. He points out how much more relaxed he is now that's he viewed as a real actor.

Raised in southern California by rocket scientist parents (funny but true), Black has straddled film and music his entire career. His spoof rock band, Tenacious D (a sort of Spinal Tap meets geeky metal head affair) is still one of his primary concerns and "The D" (as he calls them) has long stopped being a cult joke thanks to millions of record sales.

He does like his dramatic roles and the opportunity to act alongside such names as Nicole Kidman (in Margot at the Wedding). More recently he has drifted, some would say very surprisingly so, into romantic lead roles, wooing Kate Winslet in The Holiday. Is Mr Slapstick now to be referred to as Mr Sex Symbol?

"Ha ha ha, that's a good one" he laughs. "Let's just put it this way: I cannot be held responsible for people's reaction to me when I do a different type of film. The only possible reply there could be is that if anyone really, really believes that, then it is only down to the fact that unlike, say, Brad Pitt or whoever, I could be classified as 'gettable'. If you've no chance with Brad Pitt, then there's always Jack Black!

"But just on that area, I do think I could offer something a bit different on the dating scene. It's like Johnny Carson said. 'Humour is a great aphrodisiac.' But you really can't worry about who thinks what about you or else you end up sounding like you've only got audience demographics in mind when you make a film.

"Seriously, my only consideration when it comes to making a film is, would this be a cool thing to do?"

Be Kind Rewind opens on February 22nd