Benedict Cumberbatch is feeling the pressure to gain weight for his next movie role.

The 38-year-old actor - who starred in 'The Imitation Game' in 2014, and also appears in the BBC show 'Sherlock' - is said to be struggling to build muscle for his superhero role, as Doctor Strange, in the forthcoming Marvel film.

An insider told The Sun newspaper: ''Doctor Strange was always muscly in the cartoons so Benedict has to look the part when they start filming in the autumn.

''Skinny Sherlock Holmes will be the last thing anyone thinks about.''

Benedict had to undergo a similarly grueling fitness regime in preparation for his starring role in the 2013 hit 'Star Trek Into Darkness', which he subsequently described as the most physically demanding role of his career.

He said: ''I had to do a lot of training and I did a lot of eating.

''It was the first time I'd really intensely shape-shifted . . . To go up from a 38 chest to a 42, eating 4,000 calories a day and training two hours a day, as well as the stunt rehearsals and fight choreography, was the most physical demand that's ever been made of me for the screen.''

Marvel's 'Doctor Strange' will be released in summer 2016.