Saoirse Ronan and Margot Robbie battle it out in an upcoming heated historical drama about an age-old story of family ties and dueling women in power. In Mary Queen of Scots, Ronan stars as the film's titular character, while Robbie portrays her cousin Queen Elizabeth I. Intrigue about the project began back in August 2017, when Robbie was photographed on set in her character's traditional costume and drastic hair and makeup. Based on the 2004 biography My Heart Is My Own: The Life of Mary Queen of Scots, the film will hit theaters on Dec. 7. Get a preview of Ronan's and Robbie's masterful performances by watching the dramatic trailer above.