She has appeared in three feature films to date. The first was Smokin' Aces in 2007, in which she played a killer called Georgia. The film was moderately successful, but she got more attention as an actress for her role in The Nanny Diaries where she played alongside Scarlett Johanssen as her best friend, Lynette. The Nanny Diaries came out in the same year as Smokin' Aces.
In 2008 Alicia Keys played June, the youngest of three sisters in The Secret Life of Bees, a film which won critical approval and for which she was nominated for an award. She has also starred in a documentary, Muscleshoals.
She has also done a lot of acting in various TV shows and other commercial enterprises. She also has experience as a director, for example in Five, a film about women with cancer.
You can see a full list of Keys' films and other work here.