Best known for his Emmy-winning antihero of TV's The Shield, Michael Chiklis came to prominence portraying John Belushi in Wired. Here he plays Ben Grimm, the tough astronaut transformed by a DNA-altering cosmic storm into a craggy titan known as The Thing.

Jessica Alba, meanwhile, plays Sue Storm, a scientist whose exposure to this extra terrestrial phenomenon gives her the power of invisibility. Alba's other credits include Honey, Never Been Kissed, Sin City and the forthcoming Into The Blue.

Chris Evans portrays Sue's wisecracking, speed freak brother Johnny, who is endowed with control over fire as the Human Torch. Evans' other films include The Perfect Score and Cellular.

Welshman Ioan Gruffudd is known to British audiences for his performance as Horatio Hornblower in the award-winning television series. His big-screen appearances include Solomon & Gaenor, Titanic, Black Hawk Down and King Arthur.

Before making the film, how familiar were you with the comicbooks?

Jessica Alba: I wasn't actually very familiar with the Fantastic Four, I wasn't a big comicbook reader when I was a kid. So my homework when I got the movie was to read the Ultimate Series and the Marvel Night Series of The Fantastic Four.

Michael Chiklis: I'm the only one of the four that was a real, avid Fantastic Four fan. That shows my age. When I was 13 or 14 years old I used to go down to the corner store and get the latest Fantastic Four issue. I really thought I was a big comicbook fan until I went to [comic book convention] Comicon with these guys, and realised what real comicbook fans were. They put the fan in fanatic. These people, they just really live it. I knew it was going to be a little daunting when a man said to me, "Mr Chiklis, in Episode 283, when your character..." It was a little daunting at first but we were given all the source material, we looked things over and wanted to do the best job we could.

Ioan Gruffudd: To be honest I'd never heard of The Fantastic Four, I didn't know of their existence and I certainly wasn't a comicbook reader as a child. So like Jessica and Chris I'm a total newcomer to this project. Obviously we went and researched it, and very nice research it was, sitting on a beach reading comics!

Were the comicbooks themselves part of the appeal for you, Chris?

Chris Evans: There were a lot of things that drew me to this project. Mainly the fact that it was with people who had familiarised themselves with the territory. Fox had big success with X-Men, our producer Avi Arad had big success with Spider-Man, so if you're going to try and tackle a comicbook film you want to be in company that knows their surroundings. That was one of the main attractions for me.

Have you had a chance to meet some of the fans?

MC: I've had multiple encounters. At Comicon, a man about my own age came up to me dressed as The Thing. That stunned me. I've had fan mail with really passionate questions and requests, like "Please get it right!" I want to say to the people who are hardcore fans that we really did labour over every detail.

JA: I was a little bummed out that we couldn't go to Comicon this year and see what everybody thought, because we announced it officially last year. We got a standing ovation and everyone was really excited. So knowing that the movie opened and made money, and that people are receiving it so well, it would have been thrilling to go back to the fans and see what they thought. We really did labour over this and did everything we could to make it as authentic as possible.

Were you there at Comicon, Ioan?

IG: I was, but I certainly didn't get as much of a standing ovation as Jessica did. In fact they were a little bit shocked that there was this guy speaking in a broad Welsh accent - how dare this Brit represent this American comicbook icon?! Any jokes I tried to crack there was deathly silence. Subsequently, I researched the character and worked on the accent, and I think I pulled it off.

How tough was the Thing's makeup for you Michael?

MC:The big topic from day one between myself [director] Tim Story and Avi Arad was that The Thing shouldn't be CGI, that it should be a person. It obviously ended up being an incredibly arduous task being in that costume, but ultimately we made the right choice. You wanted to see that there was a human being in that body, because of the tremendous amount of pathos and humanity behind Ben Grimm. It really took the whole first week of shooting for me to start to feel like I was really embracing it, that it wasn't in control of me. But the first few days were horrible.

The screen chemistry between the four of you is obviously crucial for the story to work, isn't it?

IG: The success of the film is based on the fact that you believe they are a family, and I think that's a testament to our relationships off camera. If you have any relationships off camera it always informs what is on screen. I think you really do believe that Chris and Jessica are bickering brother and sisters, while Michael and I are best mates and I feel guilty for what I've done to him. There was definitely a lot of banter on set. To be honest, the process of making this sort of film can be quite tedious, because it's so technically based. I think we did our duty as actors to bring the characters to life and to make them three-dimensional. The visual effects team have gone and run with it, and married those elements together to create a film that's very believable within this genre.

But some of the American reviews were a little lukewarm...

JA: Anyone who is negative obviously didn't read the comicbook, didn't know what The Fantastic Four were about. They're trying to pick Academy Award-winning movies, not movies that audiences want to go to and have fun in, laugh for 90 minutes and escape their everyday reality.

MC: It certainly seemed like they were reviewing Wuthering Heights rather than Fantastic Four. That was an interesting thing to see. We all went into it knowing what it was that we were trying to make, which was a fun ride, something you go see with your family and friends or children with a big bucket of popcorn, some candy and soda. It's a jaunt, you have a laugh, it's fun.

So you'll have fun in the two projected sequels, then?!

MC: Doing this movie was sort of an hour by hour process for me, so it's hard for me to go back and transform into the Thing. But I think we all look forward to doing more. This is a long process, you shoot a movie for five or six months and then you wait another six months for post production. Then all of a sudden it all comes down to one weekend. Thank God it opened big and it's doing really well.

CE: I look at a sequel as round two for everyone involved. You're always your own worst critics when you see your performance, you get to see how the film was structured and what the final product is, and you know immediately what you could have done to make it better. So if we do number two it's just exciting to know exactly what I can do to raise my game.

Fantastic Four is released in UK cinemas on Friday 22nd July 2005.