Simon Pegg has revealed how he loved being able to let himself go for his latest film role as a slovenly writer.
The British actor, best known in recent years for his appearances in blockbuster franchises such as Mission Impossible and Star Trek, rang the changes with surreal comedy horror A Fantastic Fear Of Everything, which marks the directorial debut of Kula Shaker's Crispian Mills.
Simon plays children's author Jack, who has become so paranoid researching a new Victorian crime novel that he can barely leave the house.
The Hot Fuzz star spends much of the film looking unkempt and dishevelled, wearing very little other than a pair of dirty Y-fronts.
"It was joyous," he exclaimed. "I can't think of a better way to spend a day than just in your pants and get paid for it. It was brilliant. And utterly comfortable.
"By the time everyone had seen me once, it became a very common thing to just see me walking around... naked... and just sitting in a deck chair with my legs sprawled!"
Simon had to abandon all personal grooming to play the hairy, maniacal creature in the film. "I grew my nails out and I grew my facial hair out and I did a lot of yoga so that I lost a lot of weight," he revealed.
And yet he managed to make such a horrifying appearance amusing. "One of the great things about Simon Pegg is you can relate to him," said director Mills. "He's a real everyman.
"I think that's a pretty magical quality. It's just a gift he's got. That's why he's a movie star."
:: A Fantastic Fear Of Everything is released in cinemas on Friday June 8.