When Kate Moss told Justin Bieber to `behave`

London: Kate Moss reportedly told Justin Bieber to behave himself and be more respectful recently.

According to the source, it was during director Riccardo Tisci`s 40th birthday bash, when the supermodel, 40, was heard giving the 20-year-old pop brat some "choice words" like a teacher, after he tried to greet her in a cocky manner, suggest reports.

The source further revealed that the `Baby` singer was left speechless after the "slap in his face" kind of incident.