R&B singer Alicia Keys has joined the cast of 'The Nanny Diaries' that is starring Scarlett Johansson.

In the film Johansson appears as working class woman from New Jersey who becomes a very wealthy family's nanny. Keys will be playing Johansson best friend in the film.

According to Ananova, others starring in the film are Chris Evans, Laura Linney, Paul Giamatti and Donna Murphy. Filming will kick off later this month.