The role of Eliza Doolittle was played by Julie Andrews in the Broadway version of My Fair Lady. Andrews sang her own songs quite brilliantly.

However, Andrews had only one musical to her credit back then. Jack Warner, who wanted to make a film version of the musical, needed a famous star to portray that role and therefore, settled on Audrey Hebpurn. She was led to believe that she would sing her own songs and trained for months to perfect her singing – in fact, she was filmed while singing her own songs. Unfortunately, Warner never intended to display her singing talents. He had a soprano Marni Nixon (uncredited) dub for her. [Trivia: Nixon played the role of sister Sophia in The Sound of Music.]

The film was nominated for 12 Academy Awards in 1964 and ended up winning eight of them. Hepburn was not even nominated – it was apparently argued that she couldn’t be, since she did not sing her own songs.

The award for best actress in a leading role in 1964 went to an actress who actually sang her own songs in the film ‘Mary Poppins’.

Her name was Julie Andrews.

Listen to Andrews, Hepburn and Marni Nixon singing Wouldn't it be loverly from My Fair Lady. Scroll down to the bottom of that webpage.