Brannigan was nervous as he had never done an intimate scene before, reported E! Online.
"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," he said.
Directed by Jonathan Glazer, "Under The Sun" is a movie adaptation of author Michel Faber's novel of the same name.
