Emma Thompson has written a handbook about sex and emotion to guide her daughter through life after experiencing a horrific ordeal as a child in which she was allegedly molested by an elderly man.

The British actress has revealed she was targeted by an elderly magician at a birthday party when she was just eight years old, alleging he made a shocking sexual advance towards her.

She tells Britain's Daily Mirror newspaper, "My parents brought him to the house for my party... He was an old man with grey hair. And he took me behind a door and said, 'Would you like a sweetie (sic)?'

"I said, 'Oh yes please,' but I had a funny feeling. He gave me the sweet and said, 'Will you give me a kiss?' And I said yes. So I went up to kiss him on the cheek and he planted his mouth on mine, stuck his tongue im my mouth and wiggled it about. I thought it was my fault, children always think it's their fault."

Thompson insists the experience encouraged her to write a handbook for her 13-year-old daughter Gaia to highlight the current sexual pressures youngsters face, which she believes have become much worse through social media.

She adds, "There are so many more pressures. The sort of sexual questions being put to young kids is horrifying to me, but that's what's out there, boys and girls watching pornography, boys showing girls hardcore porn on their iPhones.

"I'm in a constant state of anxiety but I know these kids have to negotiate these thickets by themselves. We can only help by listening, being aware, by not turning away and by not saying, 'Oh, that's all so disgusting I can't even think about it.'

"So I wrote my daughter a handbook about where emotions are felt in the body, about sexual feelings and the connection between sex and emotions. And I drew pictures and said, 'You know, you can sometimes feel things in your loins you don't feel in your heart, and you need to look at that. If you listen to what's going on in your emotional language, you will be able to keep the sexual activities safe.'"