New York theatre boss James Nederlander let slip the casting during a recent interview, revealing The King's Speech star will lead the cast of his upcoming revival.

He tells the New York Post, "New generations never saw it. Colin Firth is already set. The female isn't cast yet."

My Fair Lady, the musical adaptation of George Bernard Shaw's play Pygmalion, will portray Henry Higgins, while reports suggest Anne Hathaway and Tony Award nominee Carey Mulligan are front runners to play leading lady Eliza Doolittle.

My Fair Lady premiered on Broadway in 1956, with Julie Andrews and Rex Harrison. The musical last hit the New York stage in 1993 and starred Melissa Errico and Richard Chamberlain.