"It's quite handy in rehearsals," says Stewart Cairns. "Whether they're calling for me or the mouse, we both turn round and look."

An experienced children's theatre actor full of gentle enthusiasm, Cairns is currently employed as the life and soul of Stuart Little, a New York mouse who finds himself adopted by a human family mum and dad, older brother George and the family pet, Snowbell the Cat.

Cute, furry and adventure-prone to boot, Stuart Little has already fuelled three big CGI-enabled movies. But this new stage production, which uses puppets alongside character actors, is far closer to the original tale by Charlotte's Web author, EB White.

Building on the version which ran for three months at Wimbledon's Polka Theatre over Christmas 2003, this touring show from the makers of The Gruffalo follows Stuart as he races down drainpipes and sails a toy boat through Central Park before setting out in search of his beloved Margalo, who has gone missing from her nearby nest.

"Stuart is a three-foot rod puppet so he's got a rod which comes out the back of his head and one in each elbow which operate his arms like The Muppets," explains Cairns. "But at other points in the show much smaller Stuarts appear so we can play with scale on stage."

Having initially trained as an actor, Cairn discovered the joy of puppetry when he played the red balloon in a staging of the Oscar-winning French film Le Ballon Rouge, which was also directed by Polka Theatre's Annie Wood.

"It was very good for learning the principles of puppetry because there's not much to animate on a balloon," he laughs. "The only thing you've really got is height, speed and angle. The puppet for Stuart Little is much more complicated it's got moving limbs and neck joints and all sorts."

Stuart the puppet also has a plethora of tiny props, including a toothbrush, a "borrowed" car and the pea-shooter he uses to protect Margalo when Snowbell is prowling about the lounge.

And he also has a number of costume changes, progressing from a sailor suit to a little leather jacket when he matures in the second act.

"I'm also responsible for changing him," says Cairns. "I have to hang him up no, that sounds gruesome, don't say that he gets placed in his special changing area at the side of the stage and it is like dressing a child because I have to try to get his little arms through the sleeves and he doesn't help at all. Sometimes wardrobe help but I like to be there to make sure he's got his hanky in his pocket and things."

Is Cairns, I wonder, becoming a little too attached to his puppet charge?

"I think I am actually," he admits.

"It's because when you're a puppeteer you have to build up so much belief in this object, invest so much in it.

"There's a scene where Stuart gets stuck inside the washing machine and he's very unwell. I let go of him and the parents take his body up. In rehearsals I was going 'Oh, gently! Gently!' He's just a puppet but I believed in him so much I really snapped at them!"

6pm on March 28, times vary, £12 and £10, call 01323 4120000. Stuart Little will be coming to Brighton's Theatre Royal from June 27-July 2 (08700 9008488). For review, see Thursday's The Argus.