Scarlett Johansson's 'Under the Skin' co-star was nervous about appearing naked in front of her.
Scottish actor Paul Brannigan had to strip off completely for scenes with the brunette beauty in the new thriller, and admits he didn't find the experience easy.
He told The Sun newspaper: "I was really nervous because I have never done a sex scene before.
"I was stood there completely naked in front of Scarlett and all I was worrying about was how it would embarrass my son."
Despite his nerves, Paul, 25, was complemented by 'The Avengers' star on his acting skills.
He added: "Scarlett was great. She's a marvellous girl. She said my timing was really good."
In the movie - directed by Jonathan Glazer, and shot partly in Scotland - Paul's character, Andrew, is intent on seducing Scarlett's character, Laura, only to discover she is actually a disguised alien who is hungry for human flesh.
Paul added since he got to appear on screen with Scarlett, 27, his friends have taken a much keener interest in drama.
He joked: "Needless to say all my friends are now asking me how they can get into acting."