Alicia Keys has been cast in helmer duo Shari Springer Berman and Robert Pulcini's bigscreen adaptation of bestseller The Nanny Diaries for the Weinstein Co. The pic stars Scarlett Johansson as a working-class woman from New Jersey who becomes a nanny to a wealthy Manhattan family.

Keys takes on the role of Johansson's best friend.

According to Variety, Diaries has already booked Chris Evans, Laura Linney, Paul Giamatti and Donna Murphy.

The picture, which begins lensing in Gotham this month, is based on Nicola Kraus and Emma McLaughlin's popular satirical tome.