A late addition is being made to Joseph Gordon-Levitt’s in-production feature directorial debut, Don Jon’s Addiction.  Gordon-Levitt also wrote the project and will star as a modern day Don Juan who sets out on a quest to become less of a “selfish dick” after meeting a recently widowed older woman.  Scarlett Johansson and Julianne Moore co-star in the black comedy, and now Variety reports that 21 Jump Street star Brie Larson has joined the cast as Gordon-Levitt’s sister.  Rob Brown and Tony Danza also star, with Danza playing the father of Gordon-Levitt and Larson.Larson starred on the TV series United States of Tara and also appeared in Scott Pilgrim vs. The World before landing the female lead in this year’s comedy hit 21 Jump Street.  After Don Jon's Addiction, she’ll move on to The Spectacular Now alongside Shailene Woodley, and she’s also lined up to star in director Peter Bogdanovich’s Squirrel to the Nuts.