Kirsten Dunst earns millions for a film. But what about the actor who dubs her into Spanish? The world's top voice artists tell all - in their own words

Mexico's Kirsten Dunst: Claudia Motta

I began dreaming of acting as a little girl, watching Japanese cartoons. I fell in love with the voices. Later I got into radio and then into dubbing - and I love it. After I spoke Kirsten Dunst's lines in Spider-Man, they asked me to do Mona Lisa Smile, Wimbledon, and others. She's a favourite in my stable of characters now, and I'm so pleased things are going well for her in Hollywood. I don't imitate the actor, I get into the personality of the role. I focus on the gestures and reflect that in my voice, even if there was no sound in the original. I add to the drama because to dub well you have to be as good an actor, or better. They paid me 10,000 pesos (£500) for Mary Jane in Spider-Man. The problem is that distributors don't put us in the credits. Suppose Kirsten Dunst thought, "Gosh, how nice I sound in Spanish." She wouldn't have known who the voice belonged to.

Much of my work is for television. I'm best known for playing Bart Simpson for 10 years. When different actors were brought in because of a contract dispute, the public demanded we be brought back. Mexican dubbers mostly use a kind of neutral Spanish without accents or regional expressions so all Latin America can understand. We have the best dubbing industry, and the competition in Argentina and Venezuela just doesn't have our finesse or tradition. Top Cat in Spanish has a personality and feeling that is missing in English - and I take my hat off to the woman who voiced the witch in Snow White.

France's Angelina Jolie: Françoise Cadol

Sometimes my home phone will ring and when I say "hello" there will be a sharp intake of breath at the other end. I know immediately it's a dubbing fan who has got hold of my number. Once a woman rang me and started gasping. Then after a silence, she said: "Sorry, I'm just so emotional at hearing you, I can't speak, I'll have to call back."

There are people in Paris who keep scrapbooks on dubbing, who collect signed photos, who know what you've dubbed despite your name rarely appearing on the credits. I respect people's reasons for wanting to contact me, but I don't send out photos. People feel they know the voice and they want to know you. A voice is a very moving thing. Dubbing is taken seriously in France, and people get very upset if an actor who has dubbed a star for a long time suddenly changes. Audiences want continuity.

I get invited on to TV shows to discuss dubbing - people are interested in the process. I have been Angelina Jolie since Tomb Raider because I was the voice of Lara Croft in the video games. I thought Jolie was very good in Mr and Mrs Smith - you could tell she and Brad Pitt were having a good time making that film. I don't seek out information on her in the celebrity mags, or follow her life at all, but I get on very well with the French actor who dubs Brad Pitt - a well-known actor in his own right. I'm also Gong Li, Sandra Bullock, Patricia Arquette and the voice of Mary Alice in Desperate Housewives.

I dub films because I enjoy it, it's artistic - and it is a skill that teaches you a lot about acting. I'm currently writing my fourth play for my theatre company and dubbing allows me to keep on doing the work for theatre. I've acted in theatres all over Paris, I've been on the TV, but the greatest irony is that I've never actually appeared on the cinema screen.

Italy's Renée Zellweger: Giuppy Izzo

I was born into the business. My teacher was my father. He had four daughters and most evenings at dinner he would try to teach us something about intonation. He had a saying: "Your voice is the soundtrack of your life." One of my sisters also entered the business and is now a dubbing director as well as a dubbing artist. It was a bit like growing up as a circus child, really.

My first job was as the 10-year-old daughter in The Goodbye Girl. I've no idea how many other films I've dubbed since then. I've voiced Renée Zellweger in both her Bridget Jones movies and several others. I've studied her diction, her movements and her breathing so much that I feel I know her. We've not met, though - the only actor I've both dubbed and met is Ellen Pompeo, the star of Grey's Anatomy. She came up and hugged me at a conference in Milan in the summer.

The key to this profession is obsession with detail. To get the same effects as in the original, I try, as far as I can, to imitate the actor's movements as I say her lines. Anyone who saw me working would think I was nuts. I lay down on the floor for the bedroom scenes in the Bridget Jones films. At the end of one of them, there's a scene in which Bridget is badly out of breath.

I ran twice around the block before we recorded it.

China's Tom Cruise: Ren Wei

Tom Cruise was my latest voice acting role, but I have played hundreds of parts since I joined the Shanghai Film Dubbing Studio in 1986. I was Ewan McGregor in Moulin Rouge, John Travolta in Broken Arrow, Joseph Fiennes in Enemy at the Gates, Hugh Jackman in Kate and Leopold and Vincent Perez in Fanfan la Tulipe.

But my real dream is to become a tenor. Luciano Pavarotti is my idol and I haven't given up trying to get a role in a musical. I have a good voice, dancing skills, and acting experience. I just need a chance.

I guess I was chosen to voice the Tom Cruise role in Mission: Impossible III because my age and physique are similar to his. Some people say I even look like him from a certain angle. It was a tough job. While Atang [the Cantonese nickname for Tom Cruise] had months to make the film, I had to do the whole thing - from learning the script to dubbing all the lines - in four days. We always have to rush because of the piracy problem in China. If we don't get the translation and dubbing done quickly, an unauthorised version will be out on the streets before ours.

Every day I worked for at least 12 hours. I studied Atang's voice and tried to imitate his style of talking. It was an action movie, so there was lots of running about and shouting, which was hard to emulate in a studio. It was very intense and I had to cover a big range of emotions. In the fighting scenes, it was all "Get down, get down! Go, go!" Then there were romantic moments when his voice breaks up as he tells his wife how much he loves her. I had to watch the original English version time and time again to get the feeling right.

When it was all over I was so hoarse that the director told me to go home and take a rest. The crew cracked jokes: "Tom Cruise runs so fast he breaks his legs, Ren Wei shouts so loud he breaks his voice."

I have never used the fact that I am Atang's voice actor to chat up women, but I have received letters from fans who say they really like my delivery. But that is not what is most important. My main aim is to satisfy the original actor as much as the audience.

Germany's Julia Roberts: Daniella Hoffmann

It all started out with the casting for Pretty Woman back in 1990. Back then I didn't expect it to be a big deal - more like a B-movie. I was among the finalists and I think it was my laugh that clinched it. I can do a good, really filthy laugh just like Julia Roberts -I love it when she laughs. Since Pretty Woman I've played her in every film. My vocal range is very like hers, so it all comes pretty naturally. With Ally McBeal, whom I also dub, I put on a very different voice, much higher.

I don't often get recognised as being the voice of Julia Roberts. I think women's voices are much harder to identify than men's. But being Julia has definitely brought work my way. Some adverts want the sound of "Julia Roberts" and I have also done Charlotte's Web because it was originally Julia who did the voiceover.

When I come in to record I generally haven't seen the film I'm going to dub. It used to be different: we used to get the videos to take home beforehand. But these days they are amazingly strict about new releases. When I did a voice for Star Wars, I wasn't even told in advance what film we were doing - just to turn up.

But when I play Julia Roberts I don't need to prepare or anything. I follow her lead. I mean, the woman is a great actress, an Oscar-winning actress - why should I change anything about her work?

India's Arnold : Schwarzenegger: Pawan Kalra

I've done most of the big names: I was Arnold in The Terminator and True Lies; I voiced Owen Wilson in Shanghai Noon and Shanghai Knights; and Hugh Jackman in Van Helsing. A number of people say I look like Bruce Willis and I did Bruce as the cop in Sin City. I think Brad Pitt is one of the finest. I have just done him in Spy Games - a great film. Pitt is a very fine actor who can both overplay and underplay a role. You really have to watch how he speaks, it is fantastic.

Dubbing is an art requiring a voice of many textures and tones. Not everybody can do it just because they have a good voice. Voiceover artists are cast and we have writers who make the scripts fit the lip movements of the actors on screen so that it runs as smoothly as possible. There are sometimes arguments over how to translate a single phrase.

It is hardest with black actors like Eddie Murphy and Will Smith. They are not only very funny but they speak very, very fast. Trying to street talk quickly in Hindi is extremely tough. After two days your mouth gets really tired.

My brother was in the film business. I was running my father's transport company in Bihar, out there in the sticks. But I had done some performances, so my brother said: come out and try. So I did. And here I am, eight years later.

A film for TV takes two days. I will make 20,000 rupees (£250). For theatre release it is more like 50,000 rupees (£625). It's really exploding. I do films, commercials and TV shows now. There are a lot more people saying "I heard you on television" these days. But it's a really competitive industry. When I started there were just a few people - now everybody thinks they can voice movies.

· Interviews by Jo Tuckman, Angelique Chrisafis, John Hooper, Jonathan Watts, Jess Smee and Randeep Ramesh