Alicia Keys has joined the cast of the upcoming film adaptation of The Nanny Diaries, Variety reported today.

The singer will play role of best friend to Scarlet Johansson's lead character, a college student that becomes a nanny for a rich family in New York.

The film will begin production next month and is expected to be released in 2007.

Keep up to date will all the latest news on this film in our "In Development" tracker here.