Antonio and his two wives

When I meet Antonio Banderas I am surprised not by how slight he is, or by the fact that he is wearing snowwashed denim (a fashion I thought had died out in the Eighties), or by the fact that he looks so incredibly young (he is 45, and when I remark on his sprightliness he says there were times performing the many stunts in his new movie when he felt at least 50; "Eez difficult," he says, much as Manuel would to Basil when asked to take a suitcase up to a room), but because, against expectation, I have just hugely enjoyed watching his new film, The Legend of Zorro.

As well as marking his return to the role of swashbuckling superhero that he made his own in The Mask of Zorro, the sequel reunites Banderas with director Martin Campbell and, most importantly, given their onscreen chemistry, with Catherine Zeta-Jones. But more of Ms Jones and Zorro later. First, what of that other Hollywood femme fatale in Banderas's life, his wife, Melanie Griffith?

Another surprise awaits me, for he is so open and honest and, well, genuinely sweet, when talking about Griffith, Tippi Hedren's troubled daughter who famously married Don Johnson aged 18, divorced him, married another actor, Steven Bauer, had a child, Alexander, now 21, then remarried Johnson and had a daughter, Dakota, now 16.

She and Banderas met while Banderas was married to the Spanish actress Ana Leza, Griffith was still married to Johnson. "Melanie is my soulmate and I am absolutely comfortable being with her, and I find her very beautiful. We have been now 11 years together - besides Paul Newman and Joanne Woodward, I think we are the oldest couple in Hollywood!"

Do you tell your wife constantly that you love her, that she is beautiful, to compensate for the industry you are both working in? "I do it, but I don't do it to compensate. I do it because I really feel it." He agrees that Hollywood is very cruel towards women, pointing out that Zeta-Jones's first role after Zorro was to play Sean Connery's love interest. "If you want to do it in the opposite direction," he says, "forget it."

So how did he feel when his wife set up a website chronicling with alarming honesty her various addictions, and her struggle to get clean? "I pushed her to do that, to be open," he says. "I say to her, 'You have this problem you have to share with people,' so she opened a page on the internet so people can talk to her, and I love her even more for that, for being courageous and for not hiding anything."

Banderas also gave Melanie Griffith, who is now 50, the confidence to end her other dangerous addiction: to plastic surgery. "Hollywood stars are not supposed to be perfection, I don't believe in perfection, I think it is a mistake. So, since we are together, she hasn't had any plastic surgery. I said to her, 'I want to see you growing old and I will grow old with you too, and I don't care.' I like her the way she is, wrinkles are beautiful."

They have a daughter together, Stella, who is now nine, and he says he missed her desperately when he was on the fivemonth Legend of Zorro shoot in Mexico. The £60 million film, set in the California of 1850, is that rare thing: a sequel that is better than the original, with a charm reminiscent of old Douglas Fairbanks movies and a great villain in the shape of British actor Rufus Sewell. It's out at the end of the month, in time for half-term, and is sure to be a big family hit.

Banderas did many of the stunts himself, especially when his double broke his leg during the shooting of the climactic set-piece on a runaway train. But he bore his bruises well, and that may have something to do with working with Zeta-Jones again. The first Zorro movie, in which she played Banderas's onscreen wife, Elena, launched her as a bona fide Hollywood star, and made $250 million at the box office. When Banderas and I meet, Zeta-Jones is just along the hall at the Dorchester.

"The quality I like most is not her beauty, which I recognise totally, but that she is very witty, very funny, and that she didn't change, not one leetle bit, when she became famous."