He is joined by Pierce Brosnan, Kaya Scodelario and Fan Bingbing.
The pic is helmed by Sean McNamara with James Pang, Wei Han, Paul Currie and David Brookwell producing.
Based on the Vonda McIntyre fantasy novel, the story follows King Louis XIV, who is determined to protect the future of France by reigning for all eternity. His search for immortality leads him to capture and steal the life force from a mermaid, but soon his 18-year-old illegitimate daughter discovers the mystical creature and strikes up a friendship with her.
Focus Features will release “The Moon and the Sun” in the U.S. in 2015. International sales are being handled by Good Universe.
Walker has stayed busy since “Vampire Hunter,” having finished production on WB’s “Heart of the Sea” with Chris Hemsworth and was recently seen in the HBO pic “Muhammad Ali’s Greatest Fight.” He is repped by WME and Inspire Entertainment.