Jack Black and Angelina Jolie joined Will Smith, Renee Zellweger, Robert De Niro and Martin Scorsese in Dreamworks surprising Finding Nemo-like animated adventure Shark Tale. Steve Pratt reports on the latest attempt to crack the family film market.

SCHOOL Of Rock star Jack Black concedes that his portly build may have influenced his animated alter ego in Shark Tale. "I've struggled with my weight my whole life. I'm doing the zoning thing where I cut out potatoes and bread," he says. "I don't think Lenny looks like me, maybe they got my eyes. Mine are closer together, but they got the shape of the eyeball."

He provides the voice for Lenny, a great white shark with a secret - he's a vegetarian. "He's a very sensitive and caring fish, and those are great qualities unless you're a great white shark. He has to hide from his dad so he doesn't get kicked out of the house," says the actor.

Black did get to hang out with Will Smith, whose fast-talking fish Oscar gets a reputation as a shark slayer, and shares the credits with such Hollywood legends as De Niro, who's the voice of Lenny's Godfather-like dad Don Lino. "That's good enough for me - I like that there's a poster that says De Niro and Jack Black," he says.

It was John Cusack's High Fidelity that finally got Black noticed in Hollywood in 2000 after eight years in small roles. Lacking the looks of a conventional leading man hasn't stopped him progressing to starring roles in films like School Of Rock. "I'm no Matt Damon, I wanted to be a character actor. I never thought I'd get leads the way I've been able to," he admits.

School Of Rock, featuring a struggling musician who teaches children music, is the closest anyone has come to putting the real Black on screen, he says. Off-screen, he fronts his own heavy metal parody band Tenacious D with old friend Kyle Gass.

His reputation as a rocker colours how fans react to him. "When people scream, they don't scream out, 'There goes the sexy Jack Black'. They scream, like, 'Yeah, let's rock man'. It scares the crap out of me. I think of myself as an entertainer and I sometimes pull out my acting bazooka, then I have my music machete."

ANGELINA Jolie doesn't much like the sound of her own voice, which made her latest screen role all the more difficult - saying the words for a fish called Lola in the new computer-animated movie Shark Tale.

For the Los Angeles-raised actress providing Lola's seductive tones was something new, working solo in a sound studio without her fellow cast members around her. "To do an animated film like this is a very different experience and I was just trying to make voices," she says. "It was me kind of filling those shoes because they made her very sparkly and sexy."

The vocal talent that's heard, but not seen also includes Will Smith, Robert De Niro, Jack Black and Martin Scorsese.

Jolie knew straight off which fish she wanted to voice. "There were all these different pictures of fish and I kind of looked around and saw this fish with red mouth and pointy eyebrows. I just thought, 'I know that I'm that fish'. I knew it and I liked her."

Lola follows hot on the heels of her supporting role in the recently-released retro sci-fi adventure Sky Captain And The World Of Tomorrow, playing heroic Captain Franky Cook. She was happy to leave most of the acting to stars Jude Law and Gwyneth Paltrow and look after her baby son Maddox.

"I had three days and I was able to do it quickly," she explains. "It's more about time right now because he's so young. I like films now that I can do less in."

She'll be seen in the New Year in Oliver Stone's $150m historical epic Alexander The Great, playing the leader's mother Olympias. "I was fascinated by her, she was a bit dark," says Jolie, 29.

Much the same has been said about her in the past. There were stories of tattoos, raunchy behaviour and wearing vials of blood around her neck. The daughter of actor Jon Voight also made the headlines with her volatile marriage to actor Billy Bob Thornton. All she cares about now is being a good mother to Maddox, whom she adopted two years ago.

"Becoming a parent has just completely changed me and given me such a centre and focus and so much joy," says the actress who brought Tomb Raider heroine Lara Croft to life on the big screen in two movies.

She has a home outside London as well as spending time in her son's native Cambodia. She's also committed to her role as a goodwill ambassador for the United Nations.

In the past, she feels that people have confused her with her characters. "I love being creative in films, but there was a time when I think I lived through my characters and I've now found that I prefer my life.

"Because I've played a bad girl, people automatically think that I'm a bad girl or that I'm obsessed with death. The truth is, I'm probably the least morbid person you can meet. I've been crazy in my life and I've been wild, but I've never been a bad person. I'm trying to do a lot of good things with my life."

She doesn't rule out adopting another child, although she recently confessed on American television that it's unlikely she'll give birth herself, or get married again. "I don't really know if I'm meant for marriage. Having a child would mean that this person would become a father to my son and that would have to be permanent and I haven't had a good experience with that."

* Shark Tale (U) opens in cinemas tomorrow.

Published: 14/10/2004