Based on the famously missing chapter in Colin Clark's memoir The Prince, the Showgirl and Me, My Week With Marilyn reveals the enchanted week that the then-lowly production assistant spent with the most famous celebrity of the era during the production of the classic 1957 comedy romance The Prince and the Showgirl. The year was 1956. Colin Clark was an ambitious 23-year-old determined to make a name for himself in film. As summer gets underway, Clark manages to land a position as a production assistant on the film The Prince and the Showgirl, starring Marilyn Monroe (Michelle Williams) and Sir Laurence Olivier (Kenneth Branagh). Monroe had just gotten married to playwright Arthur Miller (Dougray Scott), and the newlyweds were on their honeymoon as production got underway. Later, when Miller leaves, young Clark seizes the opportunity to befriend the platinum blonde beauty, and give her a taste of everyday life in England -- far away from the bright lights of Hollywood and the suffocating pressures of fame.