The Imitation Game actor tackles the title role as the Marvel comic book superhero Stephen Strange, a former neurosurgeon whose hands are crushed in a horrific car crash. The accident leads Strange to embark on a journey of healing, only to be drawn into the world of the mystic arts.

One sequence required Benedict and Rachel, who portrays his fellow surgeon and love interest Christine Palmer, to break down as they mourn the loss of his surgical gifts, and The Notebook actress admits she found it unusually easy to turn on the waterworks for the long shoot.

"He's so emotionally in touch with his feelings," Rachel explained on U.S. breakfast show Good Morning America as she credited his performance for helping her tear up on set. "I mean, we spent a whole day crying, and I've never cried for that long, and it was take after take after take, and I just thought, 'You're my rabbit's foot! I have to take you everywhere with me!'"

MCAdams hasn't stopped gushing about working with the British star since they started promoting the new movie, and she recently marvelled at how well he juggled filming the comic book adaptation in between stage commitments for Hamlet in London and his hugely successful TV miniseries, Sherlock.

Likening Cumberbatch to a real-life Doctor Strange, she said, "He came off Hamlet, I was watching him in Hamlet two days before we started shooting. It's one of the hardest roles on the planet, and then he was learning his Sherlock lines coming to the end of Doctor Strange, which is crazy heavy dialogue.

"I don't know, I feel like he's channelled something that Doctor Strange is channelling by the end, where he's tapped into something, some kind of force within him that keeps him going and he's got a fire in his belly. I'm just loving watching his whole career unfold."

And Rachel is overjoyed at the positive reviews of the new film: "I'm so glad people are loving Benedict's performance, I'm so happy for him," she smiled, according to "It's not easy to take on a beloved character like that, that everyone has their own opinions about and I just think he knocked it out the park."