Keira Knightley and her female prom date were told their commemorative picture was "disgusting" because they kissed.

She recalled: "We had our picture taken underneath the thing, and she's kissing me, and we were told that that was disgusting.

"Our photograph wasn't allowed - you know when you get up and you collect all the photographs of prom and you buy whatever ones you want. Ours wasn't allowed to be displayed on that because it wasn't appropriate."

And the 'Laggies' actress and her friend were also reprimanded for their choice of outfits and warned they would be banned from attending future school events if they didn't learn to "dress appropriately".

She added to Vulture.com: "We both turned up an hour late, and I'd been filming 'Bend It Like Beckham', and I turned up in leather pants and a crop top, and she was a model for a while, and she'd been in Paris shooting something, and she turned up as the boy, so she had a black tie with ripped jeans on, and everybody else was completely dressed up, obviously, in that kind of finery.

"One of the teachers took us both aside and said we were never going to come to anything if we didn't know how to dress appropriately for events like that. So that was my prom. We had a great time!"