By Chris Heard BBC News entertainment reporter

Actress Margo Stilley had originally requested her name not be used to promote the film.

But after the press discovered her identity she came forward to explain what drew her to Michael Winterbottom's controversial project.

"The film shows sex in a good light," she told The Guardian. "It is a monogamous relationship between two people who are in love."

Star defends 'sex film'

Stilley, who has no previous acting experience, spoke of the controversy, saying: "I'm surprised, and even more by the fact that I've brought most of it on myself."

She said: "It isn't shocking. If you know you are going to watch a film like this, it's not abrasive. It's normal sex that everyone has, not crazy stuff."

The film depicts the relationship between a young couple, Matt (Kieran O'Brien) and Lisa (played by Stilley), who live in London.

It is called Nine Songs because the sex scenes are intercut with film of nine concerts they attend.

The film is to be submitted to the British Board of Film Classification. Director Winterbottom said he hoped it would be granted an 18 certificate, which would make it the most explicit film ever shown in mainstream British cinemas.