The Inbetweeners' third series was expected to be the final TV outing for the show, but today Channel 4 confirmed there will be two more specials of the hit sitcom.

Channel 4 has also announced a number of other comedy commissions for digital channel E4, including new shows for Noel Fielding and Chris Addison.

E4's third series of the Bafta-winning Inbetweeners, which came to an end earlier this month, had been tipped as the last time it would be seen on the small screen. But the show will return for two one-off specials after an upcoming feature film.

Two of its stars, Simon Bird and Joe Thomas, will also feature with their comedy partner Jonny Sweet – their sketch group is known as The House of Windsor – in sitcom pilot Chickens, set in a sleepy English village during the first world war, part of a new run of Comedy Showcases on Channel 4. This is the trio's first commissioned sitcom script.

Fielding, one half of the Mighty Boosh and team captain on BBC2's Never Mind the Buzzcocks, will front Noel Fielding: Boopus, his first solo TV project, described as a mixture of sketches, characters, art and animation.

Fielding said he wanted to make something "in the spirit of Spike Milligan or the Kenny Everett Show but using modern techniques. If Dali made a show hopefully it would look like this".

The Thick of It star Addison will present Show and Tell, in which three up-and-coming comics will each bring something to "show" each week. Channel 4 said it would be a celebration of "storytelling, standup and new comedy talent".

Two former Channel 4 Comedy Showcase projects are being turned into full series. The Increasingly Poor Decisions of Todd Margaret, starring Sharon Horgan, David Cross and Will Arnett will air on More4; while Campus, from the team behind Green Wing and Smack the Pony, which is set in the "concrete hotbed of academic, administrative and pastoral tomfoolery" of fictional Kirke University, will air on Channel 4.

Channel 4 said it was investing an extra £5m in its comedy budget next year.

The Channel 4 head of comedy, Shane Allen, said: "Channel 4 continues to lead the way in comedy by backing new talent and giving established names the creative freedom to take risks. We are able to give Frankie, Noel and Chris the space to try out new things and want talent to bring their passion projects to us.

"We value our long-term relationships with people of the calibre of Victoria Pile, working with Channel 4 on her first new comedy series since Green Wing, or Graham Linehan, on the fourth series of the IT Crowd, or Sam Bain and Jesse Armstrong on their record-breaking seventh series of Peep Show; just as much as we love uncovering new talent like Morgana Robinson and Kayvan Novak.

"Channel 4's investment in comedy has risen sharply in the last two years – 2011 spend will be almost double 2009 levels – and the space Big Brother leaves puts us in the happy position of having even more hours to fill. Just as well because, God knows, we could all do with a laugh at the moment."

Other new comedy shows across the Channel 4 stable of channels include Meet the Parents, a part-scripted, part-improvised prank show from the makers of Star Stories, in which boyfriends are confronted by prospective in-laws played by actors, which will air on E4, while sitcom Peter Versus Life will return for a second series on the main channel.

Channel 4 will also air the British Comedy Awards for the first time early next year, hosted by Jonathan Ross, and devote two themed nights over the festive period to Father Ted and Peep Show.

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