Benedict Cumberbatch thinks ''diets are s**t''.

The 'Star Trek Into Darkness' actor had to stick to a strict eating and exercise regime to bulk up for his role as villain John Harrison in the new sci-fi adventure movie and reveals the process turned him into a ''creature from hell''.

He told Britain's OK! magazine: ''I loved all the working out, although there was one stage where I ate about 4,000 calories a day and then carb-depleted. It's horrible. You can turn into a creature from hell because all the fuel you're relying on to get you through the workout disappears. Now I know how girls feel. Diets are s**t.''

Rather than indulge in calorific fast food to put on the pounds, the actor opted to eat ''chicken, chicken and then more chicken''.

He told Britain's OK! magazine: ''I didn't go for junk food for the weight. It was chicken - all sorts of chicken, and salmon and protein shakes. But we tried to keep it normal food-based; carbs and protein.

''My fellow American actors would walk on set with these beautiful little bags of pre-made meals. I'd go, 'Where did you get one of those? Oh, a dietician. Can I have a dietician so I don't have to eat chicken, chicken and then more chicken?' ''