Greg Davies is shocked 'The Inbetweeners' has become such a huge success.

The comedian - who plays the role of head teacher Mr Gilbert in the franchise - was speaking at the world premiere for 'The Inbetweeners 2' in central London last night (06.08.14), where he reflected on how the show has evolved since it first aired on E4 in 2008.

Asked whether he could believe the success of the franchise, the 46-year-old said: ''No, I can't - and I'm sure anyone you speak to from the cast can't either. It's madness, it's brilliant madness.

''It's been a while since we were all on screen together and that everybody is still so excited by it is brilliant.''

Greg - who also stars as Ken Thompson in BBC 3 sitcom 'Cuckoo' - said the success of 'The Inbetweeners' is tied to the fact all the cast enjoy what they do.

He explained: ''I just had a great time on set and it's just a really fun atmosphere. The writers make sure that everyone is having a laugh and the more you have a laugh, the more it comes across on screen.''

'The Inbetweeners 2' is open in UK cinemas now.