One of the biggest challenges facing any actor nowadays is performing in front of something that isn't there. Whether it is a six foot alien with three heads, a hungry dinosaur, or a flying Yoda, the trick is in making it believable.

For Stuart Little 2 star Hugh Laurie, however, the task was relatively easy. As head of the Little family, the British actor is regularly seen dispensing words of wisdom to Stuart, the animated mouse, but, speaking at a press conference at London's Dorchester Hotel to promote the film, he reckons both he and co-star Jonathan Lipnicki, had it easy ...

"The truth is that film-making is all about imagining something that isn't there. If you had to watch the Titanic going down, they don't sink a ship just so you can look at it, they do it with a tennis ball, and you've got to watch it and pretend that your family is dying.

"So acting in this was similar. But we did have the advantage that we knew what a mouse looks like! We saw Men In Black 2 the other day and they've got to imagine 60ft aliens with nine heads coming out of the subway, so we had it easy compared to them."

It is a point endorsed by the movie's director, Rob Minkoff, who found the sequel a lot easier to film that the original, largely because everyone knew who Stuart Little was.

"The thing that made this easier, or more enjoyable, was the fact that everybody on the set knew who Stuart Little was," he explained. "This wasn't the case in the first movie, because when we were working on that one, they were basically going on a few sketches and my description, and that was a much, much more taxing thing, to try to imagine who this personality was.

"I think it wasn't until everyone got to see the movie, finished, that they suddenly went, 'oh that's Stuart', you know, so when we all got together for this one, there was a common understanding of who the character was, which made it a lot easier."

Indeed, the toughest thing about the project for Laurie was pleasing his children, who he describes as 'a pretty tough crowd'.

"I suppose my main goal is not to embarrass them too much because they've got to go into the playground and look their classmates in the eye, and if they've got other children going 'Your dad's crap!', that would obviously be tough on them! So I hope I haven't embarrassed them too much.

"But they're pretty on for this, even though they won't tell it to me. I happen to know, from other sources, that they actually loved the first one and I think they'll like this one more."

Another challenge for Laurie was creating the 'perfect' father for the Little family and, while the star confesses to attempting to draw on his own experience of being 'perfect', there wasn't too much to base it on.

"I'm afraid to say I fall rather short of the ideal in many areas," he confessed. "Mr Little is a good-hearted fellow with endless patience; that's not the case with me, I'm afraid. I'm rather crotchety to put it mildly, and something of a letdown to my own children! But there we go, I do my best and they're very forgiving, thankfully."

For co-star Lipnicki, who first shot to fame alongside Tom Cruise in Jerry Maguire, one of the more difficult challenges facing him, while filming, was balancing the demands of the shoot with his learning.

"When I'm filming, I have a tutor on set and I do three hours a day. But it's pretty hard fitting in six hours - which is what I do when I'm not acting - into three, but I guess you can do it because I'm working on a one-to-one basis so there's no interruptions. I do miss my friends, though."

Not that he intends to give the profession up, however, for the child-star has big ambitions, including venturing into directing, should the opportunity arise - he arrived at the Dorchester armed with a video camera and promptly began recording the room full of journalists!

He also loves acting, saying: "I like that you can be somebody else and not just yourself every day. If you're not an actor, you're yourself, day in day out, but when I'm acting, I can be someone completely different. That's what I love the most."

And there is no sign of the roles letting up, for he has another film, called Like Mike, about an orphan who becomes an NBA superstar, coming out later this year and will be doing a film in the autumn called When Zachary Beaver Came To Town, which is based on the novel by Kimberly Willis Holt. Stuart Little 3 may even follow after that, as Minkoff refused to rule out the possibility when asked if a third was likely.

But for the time being, all eyes are on the sequel, which opens in cinemas in both the US and UK on Friday, July 19. And the smart money says that Stuart Little will be huge.