Sure enough, the pleasant-looking bloke is Paddick. He has millions of adoring fans around the world, and his stage performances have been admired by such luminaries as Robert De Niro, Jerry Seinfeld, Sarah Jessica Parker and Matthew Broderick. Yet most people wouldn't recognise him in the street, though many would instantly know his alter ego, Captain Feathersword. For the past 11 years, Paddick has played "the friendly pirate" with the Wiggles.

He wasn't the original captain. The Blue Wiggle, Anthony Field, created the character. But Paddick is the captain the world knows - and his role has become increasingly pivotal on stage and on video. For most children, the captain is the fifth Wiggle. For most grown-ups, he's the adult relief in a show that has proved to be one of the most enduring forms of preschool entertainment ever devised. Perhaps it is symbolic that the latest Wiggles DVD, Sailing Around the World shows the captain in the centre, seemingly surrounded by his skivvy-wearing "backing group". This morning, the only piratical thing about Paddick is his earring. He's rarely recognised out of character. "It's extraordinary," he says. "It's just a patch and a hat." Yet that's enough of a disguise to allow him to lead a normal life, unlike his four colleagues. One of the drawbacks of being high-profile children's entertainers, Paddick says, "is that we have to be beyond reproach on stage and off stage".

But at least Paddick can go to the pub if he wants to. "I remember a photograph, years ago, of Murray [Cook, the Red Wiggle] watching a live band. He had a beer in his hand - and that made the photo. Just because he had a beer!" We head into the Wiggles boardroom. Yes, they have one - as befits a company that, according to BRW magazine's rich list, generated $45 million in 2004. But the boardroom could easily double as a children's playroom, decorated with a colourful Wiggles table, numerous awards and a cache of Wiggles merchandise.

Paddick isn't on the board, unlike the other four Wiggles. But he's not just another paid employee, either. Captain Feathersword isn't exactly the role he had in mind when he spent three years studying to become a Bachelor of Music in classical voice in his home town, Adelaide. "I wanted to be an opera singer," he says, cheerfully. He learned to sing "all the classic arias, in Italian, German and French", but he began to have doubts while doing "a stint in the South Australian Opera chorus". It was Mozart's Don Giovanni, he recalls. "I was a bit out of my depth - and it wasn't fun." It was then he remembered the somewhat withering advice of a former voice lecturer who had suggested his niche might be drama rather than opera. So he applied for, and was granted, a place at the Western Australian Academy of Performing Arts (WAAPA) - at the same time as Hugh Jackman.

"Hugh was actually a year below me," Paddick says. They both auditioned for the part of Gaston in Beauty and The Beast. Jackman won it. The pair caught up years later when Paddick went to see Jackman in Sunset Boulevard in Melbourne. "I said, 'You were fantastic."' But Jackman - "such a nice guy" - was equally excited about the part Paddick had just landed. "He said, 'But what about you - you're working with the Wiggles!"' The meeting that changed Paddick's life came while he was playing Diesel during the national tour of Ian Judge's production of West Side Story. When it moved to Sydney, Paddick's then-girlfriend - a fellow cast member - ended up moving into a Bellevue Hill apartment. Her landlord was Field, "who was renting out the spare room because he needed the money ... the Wiggles had only been going a couple of years".

Paddick and Field became good friends, and when the Blue Wiggle had to go into hospital for a hernia operation, "the boys" asked Paddick if he could help them out for five weeks. That was in 1993. "At that time, Anthony was playing Captain Feathersword and Wags the Dog as well. He'd pop off stage and come back, dressed up. The boys thought that it would be easier for me, rather than learning a lot of new lines, to do Dorothy the Dinosaur as well, which Murray used to do." So during each show, Paddick dashed on and off the stage playing four parts: the Blue Wiggle, the Captain, Wags and Dorothy. He counts himself lucky that they didn't ask him to do Henry the Octopus as well, "but Jeff [Fatt, the Purple Wiggle] is so small I couldn't get into the Henry costume." During this run, Paddick had a pre-arranged gig in Melbourne with Victorian State Opera singing Don Quixote in French. "And the boys gave me stick about it."

Soon afterwards, the Wiggles decided they needed a permanent Captain Feathersword, and Paddick was offered the part. He expected it to last a year, possibly two. Back then "the Wiggles were still playing RSLs, four shows a day". It was exhausting work, and not particularly creative. Gradually, though, Paddick was allowed more scope to develop the friendly pirate. "In the early days, the captain was a much smaller part of the show. He'd come on for two numbers and that was it. Now, I'm on stage most of the show, either with the Wiggles or doing my own bits."

At WAAPA, Paddick had learned circus skills - "I loved unicycling, juggling, and I'd done a bit of adult gymnastics" - so Captain Feathersword became more physical, "and a lot more manic than Anthony had been". Too manic, as it turned out. Field, Cook and Greg Page (the Yellow Wiggle, who had an operation on Tuesday for a double hernia) all had training in early childhood development "and would regularly tell me to stop speaking so quickly because the children couldn't understand me!" At first, Paddick's captain was accident prone - "I'd fall over 30 times a show, and there'd be lots more crashing into things". But the character blossomed "when Anthony pushed the magic button and said, 'You can sing'."

For many adults hearing Hot Potato for the thousandth time, Paddick's highly entertaining vocal impersonations are the high point of the Wiggles stage show. His range is eclectic: Mick Jagger, Cher, Placido Domingo - and now James Hetfield, lead singer of Metallica, another Wiggles fan. Paddick also sings "a very high falsetto", a trick he learned as a kid "singing along to the Chipmunks". He married dancer Charmaine Martin in March 2004. They now have a son, Connor John, born in February. They met when Martin was playing "Pirate Charlie, one of my friendly pirates ... and she toured with us for a while, playing Henry or Dorothy". Yet it was the hectic touring life of the Wiggles that almost proved their undoing. When she became dance captain of the separate Dorothy the Dinosaur spin-off show, the couple found they were constantly apart on different tours. "We stopped seeing each other for a couple of years because it was just too hard." It was only when she quit the Wiggles company to join her sister in a Brisbane dance studio that "we caught up again, and it just went from there".

As part of the Wiggles circus, Paddick has had to curb his natural exuberance. For example, none of the Wiggles ever touch children. And when they are photographed with children, they always adopt their now-famous "pointy fingers" pose - "so there is no doubting where their hands are", Paddick explains. "I didn't know any of that stuff when I first became Captain Feathersword," he admits. "I've got lots of nieces and nephews and I'm very hands-on." The Wiggles team insisted that touching children, however innocently, was inappropriate - and open to the risk of litigation, particularly as the monetary value of the Wiggles brand name rose. That doesn't stop the captain being an unlikely sex symbol among some mums. "It's always baffled me," says Paddick, attributing his character's attraction to "the patch, the hat and the puffy shirt". Then he adds: "I think women like the captain for the same reason Anthony won Cleo Bachelor of the Year [in 1999] - there's something appealing to women about a man who is good with kids."

Does he regret spending such a large part of his professional life saying "Ahoy, me hearties!", instead of, say, taking the path of Hugh Jackman? "I used to. I used to worry that this wasn't real acting. Sure, it might not be Shakespeare, but it's been great fun. And I've been in work for 11 years - more than anyone else who was at WAAPA when I was, except for Hugh. I consider myself extremely lucky - the travel, experiencing different cultures. It may not be a major motion picture, but I can walk into any store and know somewhere there will be one of our videos or CDs." The Wiggles perform at the Sydney Entertainment Centre on December 17, 18 and 19.

QUICK QUESTIONS

Career high? Watching Robert De Niro arrive late for our show in New York. Career low? Messing up my routine because I was too busy staring at Robert De Niro. Least-known talent? I can actually sing!

Life credo? Live it. Your epitaph? Aarrgghh!