"Star Wars: The Force Awakens'" Domhnall Gleeson and "Suicide Squad" star Margot Robbie have officially joined "Goodbye Christopher Robin," a bio pic about "Winnie the Pooh" creator A.A. Milne. Deadline reports that Gleeson will play Milne, while Robbie plays his wife Daphne.

"Goodbye Christopher Robin" follows Milne as well as his son Christopher Robin, whose toys went on to inspire Milne to create "Winnie the Pooh." The film finds the Milne family and Christopher Robin's nanny Olive as the books rocket to international success and focuses on how this impacts the family.

“I am delighted to be collaborating with Frank Cottrell Boyce to tell the remarkable and poignant story of the family behind the creation of 'Winnie the Pooh.' We are assembling a wonderful cast, headed by two actors I am longing to work with -- Domhnall Gleeson and Margot Robbie,” director Simon Curtis said in a statement.

Frank Cottrell Boyce and Simon Vaughan penned the script for the film. Damian Jones and Steve Christian are attached as producers, while David Greenbaum, Matthew Greenfield and Katie Goodson-Thomas oversee.