Robert Pattinson reveals why he passed on 'Fifty Shades of Grey'

Robert Pattinson has opened up about why he never took on the lead role in Fifty Shades of Grey, revealing the demanding physical preparation was enough to put him off.

The 40-year-old actor addressed longstanding speculation during an appearance on The Howard Stern Show, where he explained that although he was linked to the role of Christian Grey, he never became seriously involved in the project.

Asked why he turned down the blockbuster film, Stern noted that Fifty Shades of Grey author E.L. James had wanted him for the part.

"It was never really a turned-down thing. I never really got to the point where I was properly involved," Pattinson said.

When Stern pressed him on whether he had been offered the role, the Twilight star recalled meeting James before the film adaptation was announced.

"I know the writer of the book. Before any of that happened, I met her in Chateau Marmont," he said. 

"This is before the movie happened, and I found out, once her friend told me, 'Oh, that's E.L. James. She wrote Fifty Shades of Grey.'"

Pattinson explained that the biggest obstacle was the physical transformation required to portray billionaire Christian Grey.

"You just need to work out much. It's literally just gonna be exhausting," he admitted.

Stern then asked whether Pattinson had ever tried to build a more muscular physique.

"I've tried. I tried. It just doesn't work," the actor replied. "Literally, I just can't. I don't understand how people do it."

The role of Christian Grey ultimately went to Jamie Dornan, who starred opposite Dakota Johnson in the 2015 film adaptation of E.L. James' bestselling novel.