Black Bear , Artists Equity and Big Picture Co. are teaming to add some rays to A Woman in the Sun , a new feature film project from Julia Cox that will star Academy Award winners Renée Zellweger and Sissy Spacek opposite Mia Threapleton . Written and to be directed by Cox — in a reunion with Black Bear after a breakout moment penning the studio’s Nyad starring Annette Bening and Jodie Foster — A Woman in the Sun follows a month in the life of Claire Keating, to be played by Zellweger. While working as a bartender on Nantucket, part of the island’s dwindling middle class, Claire’s world cracks open when her mother gets sick and her daughter moves home. She is then forced to reckon with her past and take ownership of her future. Production is slated to begin in September. The project will get tossed into the spotlight amid the Cannes Film Festival, during which time Black Bear will introduce it to international buyers.…