Cameron Diaz is begging parents to stop telling their kids that she's the real Princess Fiona in the Shrek movies - because she thinks children should believe in green ogres for as long as possible. The actress admits she's thrilled when young fans realise her voice is behind their favourite animated character, but she believes in make believe. She says, "Parents will say to their kids when they're watching Charlie's Angels: 'Do you know who this is? It's Princess Fiona,' and they'll say, 'That's not Princess Fiona.' "I'm like, 'Don't ruin it for them, let them just have Princess Fiona. They don't need to know that's me behind her because for kids it's real.' "Kids invest in reality that way, the same way they go to bed with their teddy bear and give it a name. They probably think it gets up in the middle of the night and gets cookies. We just believe those things when we're children."