Bel Powley portrays Minnie Goetze in the film The Diary of a Teenage Girl .
The film is scheduled to be released on August 7 , 2015. A story of Minnie Goetze 's ( Bel Powley ) diary , in which she writes about her affair with her mother Charlotte 's ( Kristen Wiig ) boyfriend , Monroe ( Alexander Skarsgård ) .
The Diary of a Teenage Girl