Oscar winners Renée Zellweger and Sissy Spacek will star with rising talent Mia Threapleton in “A Woman in the Sun.” Black Bear and Artist Equity have partnered with Zellweger’s Big Picture Co. on the drama, which marks the directorial debut of “Nyad” writer Julia Cox. Black Bear will introduce the project to international buyers at Cannes. Zellweger is producing the project alongside Carmella Casinelli (for Big Picture Co.) and Kim Roth, with Greg Gertmenian co-producing. Production is slated to begin in September 2026. “Championing promising filmmakers like Julia has been central to Big Picture Co’s mission since day one, and we’re thrilled to be part of this very special project and the team who will help realize Julia’s vision,” said Zellweger. “The script is a storytelling treasure, and Julia’s instincts set her apart as an emerging filmmaker.…