Helena Bonham Carter isn't threatened by Tim Burton and Johnny Depp's friendship.The 'Harry Potter' actress doesn't get jealous of her long-term partner's close relationship with the actor and says the big screen hunk is a firm favourite with their children Billy, nine, and Nell, five. Asked if she gets jealous, Helena said: ''No, because Tim is not having sex with Johnny! No, I rejoice in the friendship! Johnny is a marvellous man and a wonderful friend. ''He is also godfather to our son Billy, and they have a wonderful relationship because Johnny is a dad himself. In Billy's eyes, Uncle Johnny can do no wrong.'' While she doesn't feel jealous, the eccentric British star - who has been in a relationship with Tim since 2001 - struggles to understand American humour and often feels left out of the filmmaker's conversations with Johnny. She laughed: ''I don't actually understand what Johnny and Tim joke about. Culturally, they have had the same childhood and I haven't, so I don't get a lot of the same telly references. They try and explain what the joke is and I just go, 'huh?' '' Helena and Johnny bonded over their mutual hatred of seeing themselves on screen and she can't even bring herself to watch her own films. She admitted: ''I can never ever watch anything. I'm in. I can't stand it. Neither can Johnny. And if it's all right for Johnny Depp to boycott his own films, I'm damned sure that it is totally OK for me.''