The heartthrob plays vampire Edward Cullen in the Twilight franchise, who in the original books by Stephanie Meyer, spends most of his time with his top off.
But the bashful Brit managed to avoid stripping off right up until the forthcoming movie, Breaking Dawn – Part 1.
And speaking at San Diego Comic-Con, he admitted that he could not have been more uncomfortable.
'The thing I was most nervous about was taking my shirt off,' he told MTV.
'I've managed to have my shirt on the whole series,' continued Pattinson. 'In the book, Edward is shirtless almost every three pages. I kept thinking: 'How can I wear a T-shirt in the sea? Or a onesie?'
'I don't want to get anyone's hopes up. I look like an inflatable frankfurter in some of those scenes.'
'At least he's honest!' his on-and-off screen girlfriend Kristen Stewart chimed in. 'That's cool.'