For the first time since Princess Diana’s death in 1997, the movie industry will pay homage to the life of the Queen of Hearts. An outpouring of tributes will flood Great Britain and the rest of the world next July when they commemorate what would have been the Princess’s 50^th birthday and the 30^th anniversary of her fairy tale wedding to Prince Charles. Two major and very different projects are currently being developed.  UK studio Pathé is banking on a traditional movie spanning her entire life from her childhood up until her tragic death in Paris, whereas Renaissance Films is taking a slightly darker approach by adapting the controversial book Diana: Closely Guarded Secret by Ken Wharfe, who served as Personal Protection Officer to the Princess of Wales for ten years, report French Elle and Britain’s Sunday Express.

Although Princes William and Harry have allegedly approved Pathé’s biopic, it is indeed very tricky to adapt the life of such a figure as Diana, complex and controversial yet so beloved. Not only the tone must take into consideration the hypersensitivity of her admirers, but its mainstream success also resides in the right casting for the role of Diana Spencer. Find out which actresses are being courted for both films and see my picks for the roles of Charles and Diana after the jump.

Renaissance Films is hoping to sign Charlize Theron opposite Ewan McGregor as Wharfe in Closely Guarded Secret, which is being produced by Stephen Evans (Much Ado About Nothing, Confessions of a Dangerous Mind).  He told the Daily Mail:

"We are intending to make the authentic movie of Diana by using the voices of the people who were there - and Ken Wharfe was right there at her side at the most significant part of her life."

Regarding the other Diana project, Pathé is reportedly courting Keira Knightley and, strangely enough, Scarlett Johansson. I am surprised that Emily Blunt isn’t an option. So far, Knightley seems to be their best bet, as she is used to playing nobility and even members of the Spencer family: in The Duchess (2008), she portrayed Georgiana Spencer, Diana’s great-great-great-great aunt whose life had some eerie similarities with that of the Princess.

To also add some extra star power, Pathé is hoping to cast Helen Mirren.  While you would immediately think it's to reprise her Oscar-winning role as Elizabeth II in 2006’s The Queen, you might be surprised to learn they want her to play Frances Shand Kydd, Diana’s mother. No word yet as who might be playing Prince Charles. It’s a hard one: Ralph Fiennes, who also played in The Duchess, is too grim, Clive Owen is too good-looking and Daniel Craig, too cool. An unknown actor would perhaps be better suited for the part.

As for Diana’s role, neither Theron nor Knightley, and especially not an American such as Johansson (also, she is 5’4” while the Princess was a towering 5’10” tall), are suitable. A most interesting – and less predictable – choice would be Oscar-nominated Carey Mulligan, an English rose who can portray both facets of Diana: the naïve ingénue as well as the manipulative and emotive “sad” royal.

With both projects still a long way from getting in front of the cameras, take all this news with a grain of salt.  Also, when competing projects about similar material are both trying to get made, usually only one of them actually happens.  More as we hear it.