What is movie with justin timberlake and mila kunis?

The movie you are referring to is called "Friends with Benefits" and was released in 2011. It is a romantic comedy film directed by Will Gluck and starring Justin Timberlake and Mila Kunis in the lead roles. The movie plot follows two friends who decide to have a no-strings-attached relationship, but soon find themselves developing deeper feelings for each other. The film was a commercial success, grossing over $149 million worldwide, and received mixed reviews from critics.