What do you remember most about Stephen Frears' High Fidelity (2000)? Is it John Cusack doing his nervous schtick to perfection? Or Iben Hjejle, the fresh face of Dogme, giving a brilliant launch to a Hollywood career that inexplicably never happened? Or one-time Cosby kid Lisa Bonet, returning from oblivion to prove once and for all that she still has the magic? Or perhaps it is Catherine Zeta Jones, playing once-hot-but-now-just-annoying like she was born to it. Well, they were all very good, but I am betting that is not it. For there was one man who eclipsed the lot of them, stealing every scene in which he appeared, and drawing all attention to his irresistible orbit. That man is Jack Black, the Robin Williams of his generation, able to make even a bad film worth watching, or conversely able through sheer gravitational pull to make a decent film implode. Awesome singing voice too.

Even when he steps into the screening room at London's Soho Hotel for a press conference, jet-lagged, bleary-eyed and peroxided (the latter, as he is quick to point out, "for a role - this is not my choice, it's not fashion"), he has an irrepressibly commanding presence, like some hyperactive imp for whom the critics in the audience are merely amusing playthings. He is here to promote Michel Gondry's Be Kind Rewind, a film which is the perfect vehicle for his manic talents. In it, not only does he play the main character's trailer-dwelling sidekick Jerry, but also a host of more familiar Hollywood roles, from one of the Ghostbusters, to Robocop, to the titular lead of Driving Miss Daisy, in a series of lo-fi VHS camcorder remakes (or 'Sweded' versions, as they come to be known in Gondry's film).

Gondry apparently discouraged the cast from rewatching any of the original films whose parts they reproduce with such hilarious amateurishness, and Black claims not even to have seen Rush Hour 2 once. "We didn't redo High Fidelity", Black reveals, both because it would have led to "a tear in space-time", and "would have taken you out of the movie within the movie". He is not sure if Sigourney Weaver, who plays a Hollywood studio executive in Gondry's film, has yet seen the 'Sweded' Ghostbusters, or how Jackie Chan, who has recently contributed voicework alongside Black to Kung Fu Panda, will respond to Black's thighslappingly funny impersonation of him in the 'Sweded' Rush Hour 2. Most tantalising of all, Black alludes to rehearsal sessions for other 'Sweded' movies (he specifies Back To The Future) which had to be abandoned when, in a true case of life imitating art, they failed to get the proper legal clearance.

So much for the film, but what about Black's own life? Rather surprisingly he is insecure about his acting abilities ("every movie I do I'm always worried it'll be my last movie - 'cos I suck so bad"), and perhaps less surprisingly he is uncomfortable with the Hollywood scene ("I'm kinda a pigpen kid in a big industry"). And did he have any more personal details to impart to his fans? Well, yes - as a young boy he used to force his dog to run through mazes that he had fashioned from cushions, to slide down stairs in a sleeping bag, and to "put Coco Puffs in my butt". Pray why, Mr Black? "I was a scientist."

Anus-oriented experiments aside, if you want to see Jack Black's best side, go out of your way to see him in Be Kind Rewind and Noah Baumbach's forthcoming Margot At The Wedding. The former is a wonderfully quirky film that showcases all of Black's madcap skills, while the latter, though merely middling as a follow-up to The Squid And The Whale, features one of Black's very finest (and most restrained) performances to date.