Jamie Dornan has teased his co-star Dakota Johnson over the amount of boyfriends she's had in the three years they've been shooting the 'Fifty Shades of Grey' franchise.

Jamie portrays handsome S&M enthusiast Christian Grey in the erotic films, with Dakota playing his lover Anastasia Steele in the trilogy of erotic dramas, which come to an end with 'Fifty Shades Freed'.

The 35-year-old actor - who is married to songwriter Amelia Warner - insists he and Dakota, 28, have a very sibling-like relationship and he has felt protective of her when it comes to the various men she's dated whilst they've known each other.

Speaking on 'Jimmy Kimmel Live!' on Wednesday night (31.01.18), he said: ''This is going to sound bad, but it's almost like brother-sister. Because I am married and she's had quite a lot of relationships in the time that we've known each other, so that's happening in our own lives. You just sort of have this mutual love and respect for each other. I feel we know each other so well - intimately.''

And, although there are a lot of sex scenes in the films, the producers try to limit the amount of people in the room during the frisky takes out of respect for his privacy.

He explained: ''The producer try to keep it only whoever really needs to be in there, like me. They try to sort of minimise how many people are in there.''

However, Jamie's genitals aren't completely on show because he get to wear a modesty pouch, and he has joked that he needs a ''huge'' bag because his manhood is so big.

Jamie - who is from Ireland - quipped: ''I wear a wee-bag. Well, that's an expression from where I'm from - a wee-bag. But it doesn't mean it's actually wee in size. I wear quite a big bag! I wear this huge travel bag and stuff everything in there.''

And, although he's been filming the blockbusters for three years, Jamie is still waiting to get his own pouch - also known as a c**k sock - as he's always had a second hand one.

He added: ''I'd love to get to the stage where you have your own one that you get to carry around. I think I was right to think this way: On the first movie, there was a selection of them, and I picked one. I thought you'd take them out of the packets and they'd be brand new; they'd have that brand new smell. Then I sort of picked one that I liked the look of and the shape of, and in the seam it said, 'Inmate No. 3.' It was sewn into it. I was like, 'S**t. This has been used before?' When you picture the guy playing Inmate No. 3 in a movie in your head ... I don't know. It's not sexy!''