The Weinstein Co. has set an April 21 launch for its Robert De Niro family comedy “The War with Grandpa”, Variety reports.

Tim Hill will direct the film, based on the 1984 children’s book by Robert Kimmel Smith, in which a boy is forced to move out of his room when his recently widowed grandfather moves in. With the help of his friends, the boy devises outrageous pranks to make his grandfather surrender the room — but he turns out to be tougher than expected and all-out war ensues.

Phillip Glasser, Marvin Peart and Rosa Morris Peart are producing with Jane Rosenthal and Barry Welsh exec producing. Lisa Addario and Joey Syracuse wrote the first draft and Matt Ember and Tom Astle are currently doing a polish on the script.

Marro Films is financing and producing with Dimension distributing. Hill’s credits include “Alvin and the Chipmunks” and “Hop.”

De Niro was attached to the project last month.

The film has not been shot yet. “The War with Grandpa” will open against Warner Bros.’ thriller “Unforgettable,” starring Katherine Heigl and Rosario Dawson, and Disney’s documentary “Born in China.”