Benedict Cumberbatch has revealed how "psychologically and physically" demanding his Doctor Strange role was.
The 40-year-old was told by Marvel's president Kevin Feige that it was the toughest regime they had ever put an actor through.
Benedict told The Sun: "He goes through so much psychologically and physically, which I can testify to as an actor.
"Kevin Feige went, 'I don't think we have put an actor through quite as much as this.' I said, 'I'll wear that badge with pride.'"
Benedict said his preparation for the role was made even tougher due to long working days, and very little sleep thanks to his 14-month-old son Christopher, his first child with wife Sophie Hunter.
He said: "It was a tough shoot... It was very, very physically demanding.
"Not just getting all hench, as they say in Wales, the buffness you need for the superhero stuff.
"But also just day-to-day fitness and the stamina to do 14 to 15-hour days with very little turnaround and very little sleep and a baby at home, and all the rest of it.
"So I did go through quite a lot. No pain, no gain. But for the character, hopefully it'll show."
Ben plays neurosurgeon Steven Strange, who turns to mystic powers when his career is ended in a car accident.
Doctor Strange is scheduled for release in UK cinemas on October 28.