Suki Waterhouse was mean to her nanny as a child.

The 21-year-old model and her three sisters, 14-year-old twins Charlie and Madelenie, and 19-year-old Imogen, were mischievous children and often played tricks on those who looked after them.

Suki said: ''Me and my sisters were so awful. One nanny, we loved, but we hacked her email and sent her boyfriend lots of weird messages, and we once actually locked her in the toilet, too.''

Suki admits she often clashes with her family because of their ''big personalities'', though they sometimes get on equally well.

The model explained: ''There are a lot of us, and we're all big personalities. So we can be in hysterics, or someone will leap out of the car in a rage because of an argument.

''My dad once did that, actually. We rode home with him clinging to the bumper.''

The blonde beauty is dating 'Silver Linings Playbook' star Bradley Cooper and doesn't like to ''go on'' about him - as she doesn't think she could stop.

She told the January edition of Britain's Elle magazine: ''I'm not one of those girls who goes on about their boyfriends. I do think whatever I say will sound weird. But the truth is, if I start talking about him, I probably won't be able to stop.''