American actress Jessica Chastain has been confirmed as Princess Diana in upcoming film Caught in Flight, focusing on the controversial love story between the Princess of Wales and Pakistani surgeon Dr. Hasnat Khan. The script and casting are already facing controversy however, as reports indicate the production will paint Diana as a damaged person and have cast Chastain, a largely unknown American, to play one of Britain's most iconic royals.

Chastain, who made a name for herself in 2011 with breakout performances in Tree of Life, The Help, and recent thriller Take Shelter, certainly has the talent to play the mother of Prince William and Prince Harry. Jessica Chastain was up for an Oscar for Tree of Life, and has received consistenly rave reviews for her work.

Putting on a British accent for the first time however, is always risky for young actors, and notoriously difficult for Americans (see Anne Hathaway's Mary Poppins-like turn in One Day). Chastain has never attempted to play a Brit before. She joins Meryl Streep on a growing list of American actresses in British films about British icons, and UK public reaction to Streep in The Iron Lady has largely been negative.

Far more controversial than the choice of Chastain to star however, is what has been leaked about the plot of Caught in Flight, which is said to paint the beloved princess in a very unflattering light.

Controversy: A lot of people will not be happy with this movie.

Penned by Steven Jeffreys, screenwriter of Marquis de Sade biopic The Libertine and directed by Germany's Oliver Hirschbiegel, known for Hitler biopic Downfall, the movie will focus on the post-Charles divorce period from 1995 to Diana's death in 1997.

Described as a love story between a princess locked in a tower and an ordinary man, the film is set for pre-production in March 2012, and pictures the beloved princess as a love-struck stalker desparate to win Khan back after their breakup, which occured months before her tragic death.

Princess Diana met Dr. Khan in 1995 at Royal Brompton Hospital and immediately fell in love with the heart surgeon. Friends report her calling Hasnat Mr. Wonderful and wearing traditional dress while visting his parents in Pakistan, even considering converting to Islam so that she could marry him.

According to IndieWire however, those who have read the script for Caught in Flight say the film focuses less on what might have been between the couple and more on how dependent Diana was on Khan's love. She is shown as an emotionally fragile and damaged woman who followed Hasnat for weeks after the affair ended.

Hirschbiegel has made it clear, while shipping the film to investors at the American Film Market in California, that he views Khan as a wise and compassionate figure, while looking to examine, in vivid detail, the unflattering psychological demise of a woman denied his companionship. The UK-based company producing the movie, Ecosse Films, is known for movies like Lennon biopic Nowhere Boy and Her Majesty, Mrs. Brown, about an alleged affair between Queen Victoria and one of her servants.

Such an angle from the biopic movie producers, including the reported take that the princess's affair with Dodi Fayed was little more than a way to make Khan jealous, is sure to provoke the ire of die-hard Diana fans.

It will also be interesting to see if Khan, who has remained almost completely silent about the two-year affair, will react to the film, and whether he will make any statement about the production.

Caught in Flight will be filmed in Paris, where the Princess of Wales died in a tragic car accident, as well as the UK, Pakistan, Angola and the south of France.

We're expecting a lot of people will not be happy with this movie, an insider told The Daily Mail. But it is a fabulous story, and one that needs to be told.

Diana, William and Kate Biopics Flopping

Caught in Flight is the third Diana biopic in the works. Producer Stephen Evans is trying to get a $30 million adaptation of Diana's lifelong bodyguard Ken Wharfe's book Diana: Closely Guarded Secret. The production is set to star Charlize Theron and Ewan McGregor, but has had no luck in the past year. Pathé films meanwhile, have long tried to grab Keira Knightley for a broader biopic of the Princess of Wales, but Knightley turned it down for The Duchess and has put off the offer ever since.

The film's production also follows another controversial royal drama starring Diana's son, Prince William, and new wife Kate Middleton. William and Kate premiered just before the royal wedding, and the American actors playing Prince William and Kate Middleton were panned for their hammy accents, while the TV film was ripped by critics for being truly terrible: shoddily cast, poorly executed, badly edited and surprisingly boring.

Caught in Flight may have better luck than its companions, as Princess Diana remains a fascinating, controversial and mesmerizing figure for both Britains and Americans, and details on her affair with Khan have always been scant.