Kate had the lead role in the 1993 musical about a poor flower girl who is taught to pass herself off as a duchess.
She took the role incredibly seriously, committing to the accent so completely she had the audience in stitches.
Kate took part in the play while studying at the $25,000-a-year St Andrew’s School in Berkshire.
Friends at the time say she struggled with the Cockney accent but “took to being a lady like a duck to water”.
Kate’s love interest in the production was played by Andrew Alexander, who went on to become a famous actor starring in Downton Abbey. He is believed to be one of Kate’s first crushes.
“Kate was very shy around him because she had a huge crush on him,” a source told The Sun.
