Heartthrob Jamie Dornan has revealed that he glued part of a wig to his “private parts” as a late-developing teenager – in case he got lucky.

The Fifty Shades Freed star tells The Graham Norton Show that when he was 15 he “looked seven” and was “quite small and wasn’t hairy at all”.

He tells the BBC One show, which also features Dame Helen Mirren and Liam Neeson as guests, that he tried to appear older at a party he went to, straight after appearing in a play.

Dame Helen Mirren, Liam Neeson and Jamie Dornan on Graham Norton's show (Matt Crossick/PA)
Dame Helen Mirren, Liam Neeson and Jamie Dornan on Graham Norton’s show (Matt Crossick/PA)

“For my role, I had bits of a black wig glued to my face for a beard and I decided to keep it for the party so I would look older,” the 35-year-old says.

“I also decided to cut up the rest of the wig and glue it to my private parts just in case I got lucky.

“I didn’t get lucky and removing the bits of wig ripped out the very small amount of natural hair I had down there. It was a physically and emotionally painful experience!”

Dornan also says that a scene which appears in a Fifty Shades Freed trailer, showing the actor emerging from the sea, was in reality anything but sexy – because he was wearing jelly sandals.

“What you can’t see is that it was pebbly and I couldn’t walk on it. The beach was only semi-closed and there were lots of people taking photos as I struggled up the beach,” he says.

“It was so not cool. They even put down a piece of carpet for me to walk on but I still struggled. In the end, I had to wear a pair of jelly sandals and no-one looks sexy in those!” he says of his James Bond moment.

And he says of wearing a modesty pouch on the set of the films: “I was given a selection – for size I guess – and when I found one that fitted I took it off and noticed inside a label that said, ‘Inmate number three’. Clearly it had been worn before. I just had to grin and bear it.”

Dornan shot to fame as a serial killer in TV hit The Fall.

And he says that it was flattering to hear that his character gave women nightmares.

“A lot of women told me that they couldn’t watch it alone and that I gave them nightmares, which is a compliment I guess because I wanted the character to be frightening,” he says.

The Graham Norton Show airs on BBC One on Friday at 10.35pm.