Madonna - who split from British film director husband Guy Ritchie in October 2008 - was originally planning to play the part of Wallis, but has since reconsidered and is now said to be in talks with 'Up In The Air' actress Vera Farmiga.
The '4 Minutes' star - who will direct the movie - revealed recently that she wanted British star David Tennant to play the monarch, but is said to have changed her mind.
Madonna's only other directing credit is 2008's 'Filth and Wisdom', which starred Richard E.
Grant and Eugene Hutz, although she has served as a writer on documentary 'I Am Because We Are'.'W.
Partygoers were also treated to a performance from Gogol Bordello singer Eugene Hutz, who duetted with Madonna during her incredible closing performance at Live Earth London.
Hutz played with Russian gypsy act The Kolpakov Trio, and their Romany-inspired set is said to have gone down a storm with the birthday girl and her guests.
Some more info on for us Madonnaholics: "Described as a comedy/drama/musical/romance, the story features a Russian immigrant, ballet school, lap dancing, cultural revolution, poetry, night club, punk rock band, book writer, dominatrix and gypsy.
Madonna allowed additional dialogue written by Eugene himself to be included in the film.Filth and Wisdom, a sprawling comedy, is a celebration of London’s ethnic stew, and stars Eugene Hutz as a Ukrainian gypsy with an intensely annoying habit of looking the camera in the eye and spouting gobbets of wisdom that have as much relevance to real life as Chinese fortune cookies.Hutz’s hero, Andriy, shares a dilapidated house with a collection of similarly unlikely characters.On that occasion, the 'Hung Up' singer was thrown from a new horse that Guy had arranged as a special treat.The fall left Madonna with several cracked ribs, a broken collarbone and a busted hand, and she had to undergo months of physiotherapy and Pilates before she was back to full health.