Claim: Marilyn Monroe played the lead role in Gentlemen Prefer Blondes.
Evidence: By 1953 , Monroe was one of the most marketable Hollywood stars , with leading roles in three films : the noir Niagara , which focused on her sex appeal , and the comedies Gentlemen Prefer Blondes and How to Marry a Millionaire , which established her star image as a `` dumb blonde ''.