WELSH actor Ioan Gruffudd admits to having two left feet on the dance floor, which made his spectacular dancing scene in the new Fantastic Four movie all the more thrilling.

He's like a bendy, stretchy version of John Travolta's disco dancer in Saturday Night Fever as his character Reed Richards struts his stuff on the dancefloor with a bevy of attractive women.

The fact that he's not only a scientist and the world's brainiest man but can also stretch and bend himself into ridiculous positions makes his dancing display pretty amazing. "That performance is thanks to the special effects team really," admits Gruffudd.

"Although I did have a week of intensive choreography sessions, which wasn't such a bad thing because I was surrounded by three gorgeous actresses who played the dancers.

"That whole scene took almost three days to do all-in-all because the nature of shooting a scene with special effects is that you do it several times with the actors there and several times without them there.

"That was the embarrassment of the situation, being up on that stage on my own performing the dance and pretending that I'm enjoying myself, while I'm being incredibly self-conscious with all the extras and other actors sitting there watching me."

On the plus side, he's pleased to see Reed Richards more confident, more relaxed and having fun in Fantastic Four: Rise Of The Silver Surfer. In the first film, he came across as a nerdy scientist without much a life. In the second, he's preparing to marry Sue Storm, alias the Invisible Woman when not uttering ridiculously complicated scientific terms. "I was just pleased I got it out in the American accent. That was one of my greatest challenges," he says of his tongue-twisting technical dialogue.

"I'm very proud that Mr Fantastic has evolved from being the nerdy scientist guy to the leader of the Fantastic Four, the father figure, the husband, the lover, the friend. I'm just pleased with that evolution.

"I was very excited when I read the script. All the characters are so well-established now and we took our time to enjoy their relationships. That's what makes a good movie - a good story and good characters. You can have all the special effects in the world and unless they're married into a fantastic story, then there's no point.

{I think compared to a lot of other franchises that are out there, we have a fantastic story to tell."

Filming what we can call the stretchy-bendy scenes in which Mr Fantastic demonstrates his particular skills is incredibly repetitive, he says, requiring a lot of concentration and imagination. "The satisfaction is seeing it all put together, to see it on the big screen. That makes it all worthwhile," he adds.

He's used to being approached by fans, usually younger ones. Predominantly, he says, he gets collared at baggage claim. "There's nothing quite like that wonderment in a kid's eyes," he says. "I always try to play a little trick, put my arm up my sleeve and say that's as far as I can stretch today, or say the Invisible Woman is there but she's shy."

For Jessica Alba, playing the Invisible Woman must be the ideal role in some ways as she's determined not to be cast on looks. This can be difficult when you look like Alba, whose break came when, as a 17-year-old, she was picked from more than 1,000 candidates by Titanic director James Cameron to play the lead in his TV series, Dark Angel.

Since then, she's moved into movies such as Sin City and Into The Blue. She's also a lads' mag favourite, featuring regularly in most desirable or sexiest women lists. FHM named her 2007's Sexiest Woman In The World. She finds it bizarre, saying that "when I was young, no one every asked me out on a date. I was nobody's type, so this is very weird. But, yes, it is flattering".

SHE'S eager to escape being cast on her looks alone. In a recent interview, she said she wanted to be taken seriously as an actress but is prepared to do movies that she would otherwise not be interested in to build her career. Once established, she can afford to be more choosy.

She already has a no nudity clause in her contracts. "I don't do nudity. I just don't. Maybe that makes me a bad actress. Maybe I won't get hired in some things. But I have too much anxiety," she has said.

Alba will soon be seen in a comedy, Good Luck Chuck, and a medical thriller, Awake. "It's great because I look normal. I'm not fighting anyone and I don't have to wear a bathing suit," she says.