Harry Potter actress Elarica Gallagher has been cast as Marvin Gaye's wife in director Julien Temple's much-anticipated biopic about the tragic soul legend. Gallagher, who appeared in Harry Potter and the Half-Blood Prince, has joined a cast that features Brendan Gleeson and S. Epatha Merkerson, who will play Gaye's mother. Jesse L. Martin will portray the soul man. The untitled project is among the films being presented to buyers at the Cannes Film Festival in France. Temple's film will focus on the 18 months Gaye spent in Belgium recording the album Midnight Love.