The poster shows Ronan and Robbie standing tall in coordinating gold dresses and similar hairstyles. The image features the movie's tagline, "Bow to no one."
"These queens bow to no one. #MaryQueenofScots," the film's official Twitter account captioned the post.
Mary Queen of Scots will dramatize Mary's real-life attempt to overthrow Elizabeth, her cousin, and take the English throne during the 16th century. The movie is based on the John Guy biography The True Life of Mary Stuart.
"She's brilliant," Ronan said of Robbie in an interview with MTV News in May. "We were really a driving force for each other."