UNDERWORLD star Kate Beckinsale had a very overactive imagination as a child and feared she was being poisoned by her au pair.

The actress feared she would spontaneously combust and also that she was being murdered by her minder.

Beckinsale recalls, "I worried because we had a very quiet German au pair and I used to write letters to the fairies every weekend.

"My mother still has a note that I wrote saying, 'Dear fairies, hope it's going well in fairyland, and is the au pair putting poison in the jam tarts?'

"I thought she was poisoning me. She was really there just to learn English, not murder me. (The letter) should have launched an investigation. It's kind of upsetting (that it didn't)."