Hugh Jackman and Garrett Hedlund are also on board with Joe Wright set to direct.
Sources say an open casting is being held to fill the role of Pan, as the character is between 10 and 12 years old.
Jason Fuchs penned the script with Greg Berlanti, Paul Webster and Sarah Schechter producing. Courtenay Valenti is overseeing for the studio.
The film will be a new take on the classic story. It is set during World War II and follows an orphan named Peter who is kidnapped by pirates and brought to Neverland, where he discovers he’s destined to save the land from the pirate Blackbeard.
The world being created is multi-racial/international – and a very different character than previously imagined.
The studio took on an exhaustive search in finding the right girl to play Lily looking at other actresses such as Lupita Nyonog’o and “Blue is the Warmest Color” thesp Adele Exarchopoulos before going out to Mara for the role.
WB dated the film for July 17, 2015, and sees it as a franchise that can appeal to the “Harry Potter” and “The Lord of the Rings” fanbase.
Mara just started production on the Todd Haynes pic “Carol” starring Cate Blanchett and was most recently seen in Warner Bros.’ “Her.” She is repped by WME and Management 360.