Saoirse Ronan has signed on to star in Mary Queen of Scots for Working Title and producers Eric Fellner and Tim Bevan.
Michael Hirst (Elizabeth: The Golden Age) wrote the screnplay, with the producers currently seeking a director. Mary Queen of Scots was crowned the Queen of Scotland before her first birthday. Her first husband also became the King of France, making her the queen consort in 1559.
Her reign went downhill from there, after marrying her first cousin before he was murdered. She then married the man accused of killing her former husband, which caused an uprising that resulted in her imprisonment. She was executed at the age of 18, for her alleged part in an assassination attempt on England's Queen Elizabeth I, Mary's cousin.
If a director can be found in the near future, the producers hope to start filming sometime next year.