He has entertained youngsters across the world for ten years with his jolly demeanour and cheery smile.
But new sketches reveal that Bob the Builder was not always the friendly, helpful chap we have all come to know and love.
Early drawings of Bob show him to be a grumpy old soul with hands on hips and sporting a dense moustache.
The pictures have been unveiled as Bob prepares to star in his first feature length movie which will star a host of new characters including Dicky Olivier, a local theatre manager, museum director David Hockney, Brickbeard the Pirate and rookie digger Scratch.
Speaking to the Telegraph, Keith Chapman, who created the character of Bob the Builder, said it all began when he spotted a JCB on his way to work.
“I saw a JCB digging up the road in Wimbledon and stood there and sketched it on my way to work,” he told the newspaper. “I sketched other machines, a dump truck, a crane, a cement mixer and a steam roller.
He added: “I felt they needed a father figure and came up with Bob. But it was a toss up between Bill the Builder or Bob the Builder. And Bob won.”