With so much material required, Gigglebiz producer Michael Towner commissioned writers from BBC Entertainment's Comedy School to work alongside CBeebies' more traditional writing squad and Justin himself. The writers combined credits include work on shows such as Have I Got News For You, The 11 O'Clock Show, Dead Ringers, Armstrong And Miller, Bremner, Bird And Fortune and The Friday Night Project.

With a 12-week filming shoot, 10 weeks in the edit suite, around 250 sketches and 20 different characters all played by the same man, Michael could be forgiven for not seeing the funny side of Gigglebiz any more. But fortunately he is still chuckling, a fact he attributes to the talent of Justin Fletcher: "We do have a laugh, sitting in the edit suite," says Michael. "I've seen all the sketches a million times now and I still sit here giggling away. There's a real variety of characters, the majority created by Justin himself."

"Justin is amazing and so versatile because you can watch him back-to-back in two sketches and you know it's him but he somehow manages to be completely different. There's something chameleon-like about him. He morphs into different characters and you totally believe those characters for as long as they are on the screen and then he's on to something else and you believe that one."

It's one thing making adults laugh but quite another to make a four or six-year-old child laugh, which is where Michael says he thinks Justin's talent really lies: "I think Justin just gets comedy. It's very interesting, actually, if you are out filming with him - and we often are in places where there are children close by and they are just drawn to him. There is something about him which they just are mesmerised by and it doesn't matter what character he is dressed as, they will spot him and they know him and they are happy to come up to him and say 'hello'."

"In terms of his comedy skills he just gets what makes that age range laugh and he is able to somehow channel it through this body he's got and his face. It's quite a skill and very, very few people have it and it's great to watch it at work."

Although many of the comedy creations are Justin's own, with so much material to write, Michael was keen to enlist writers from a variety of different sources. "I have 30 writers working on the show which I gathered from a variety of sources. With so many characters and so much material to fill I felt it was the best way to get a good spread of ideas," he explains. "There were writers who are very experienced sketch show writers who have done lots of work for BBC Radio 4 or BBC Television, some writers came to me via the BBC's Creative Comedy College and there are some in-house staff writers who wanted experience at writing sketches so I gave them the opportunity - so a real variety".

Again, writing comedy for adults and for young children are two very different things, as Michael explains: "It is very different and I had to ask a lot of the writers to do little statements or sketches to show me whether I thought they had the right tone and it's amazing how many writers don't. Young children don't get references that even an older child might automatically get so you have to be a little bit more literal about the comedy. Slapstick always wins because it is timeless and that is why a lot of these characters are silent characters which rely on slapstick."

"There's an awful lot of the world that this audience hasn't yet experienced so I think that hopefully what we've done is to strike a balance between entertaining them but also including enough material so that when the mums and dads sit down, and indeed older brothers and sisters, there are going to be sketches that they can enjoy as well. It's a very fine balance and you have to be quite strict with writers about what they can and can't do."

So, despite a punishing filming schedule, Michael will be sorry when the process finishes?: "Every day has been a joy to go out," he says.

"Twelve weeks is a very long time to be filming, every day and in all weathers and conditions, but there's been the fun of doing what we do and remembering why we are doing it and a lot of that comes from Justin. I've enjoyed watching this creative process happening before my eyes - watching everybody chipping in with their own creative ideas in their own area and just making it better in their own way."

"It has been huge fun and it's going to live with me for a long time."