WHEN Grace Kelly announced she was turning her back on Hollywood to marry a prince, the actress's recording studio demanded it be present to film what it predicted would be the wedding of the century. Only then, said MGM, would it free her from the film contract that she was breaking to begin her new life as Grace, Princess of Monaco. The video recording from 19 April 1956 was the last time Kelly's fans saw her appear as the quintessential film starlet whose every move, word and gesture, on and off camera, was directed by the film industry. For decades afterwards, until she died in 1982, the life of the actress turned princess was shrouded in mystery. When she was killed in a car accident while driving with her daughter through the mountains of Monaco, her death was surrounded by the same intrigue as followed her throughout the final years of her life.

This week, for the first time, the palace of Monaco has opened up its archive of the princess's personal belongings. An exhibition, opening this week in Monaco's Grimaldi Forum, marks the 25th anniversary of her death.

The collection includes her final reel of MGM video tape, a host of revelatory video recordings that show a relaxed Kelly as a mother and wife, and grainy behind-the-scenes footage she took after her friend, the director Alfred Hitchcock, taught her how to use a camera.

Some home videos feature Kelly reading a map to her children, Princesses Caroline and Stephanie and Prince Albert, while her husband, Prince Rainier, drives the car on a family holiday.

Others show her children dressed as Native Americans, and Kelly peering out of a window in a chalet in the Swiss Alps.

The material reveals Kelly to be an avid letter writer whose personal correspondence included letters from Hitchcock planning visits to Monaco, and from Jackie Kennedy, thanking Kelly for her support in her husband's political campaign.

Popular Hollywood legend holds that Hitchcock felt "abandoned" when she decided to marry a royal, and that that was the reason he did not attend their wedding. But the archive reveals that her friendship with Hitchcock did not become frosty after she left acting, and that he continued to write and visit.

Until now, the archive has been locked away by the royal family following Kelly's untimely death on 13 September 1982. Then aged 52, Kelly had a long-standing fear of driving, and is said to have suffered a stroke that led her to veer off the road, causing her car to plunge down the mountainside.

Rumours that mother and daughter were arguing heatedly over Princess Stephanie's apparently unsuitable boyfriend when the accident occurred have persisted over the years in spite of repeated denials.

The decision was made to show the collection of personal items, which had before been deemed too "raw" to bring to an adoring local public, who were gravely shocked when she died.

Kelly, who was born in Philadelphia in 1929, was one of the most popular actresses in the world in 1954, when she appeared on the front cover of Timemagazine and won an Oscar for her performance in Country Girl.

Her collaboration with Hitchcock further elevated her to legendary status. She starred in Dial M for Murder, Rear Window and To Catch a Thief, where she discovered the principality of Monaco during shooting. The film is believed to include a scene where she drives down the very section of road where she died decades later.

In 1954, she met Prince Rainier on a visit to the palace of Monaco, during the Cannes Film Festival. The meeting changed the course of her life and, following the Prince's visit to the Kelly family that Christmas, the announcement of her engagement generated a media tornado. Implicit in her decision to marry the Prince, who was famously private, was a rejection of the acting industry.

The exhibition's curator, Frederic Mitterrand, the nephew of former French president Francois Mitterrand, said her story was being told with honesty.

"I am addressing this experience with the greatest candour. I think we all have an idea of what a wonderful person Princess Grace was, but at the same time that idea has been frozen for 25 years and is limited to a few powerful, beautiful, moving images that perhaps do not sufficiently express her diverse and complex personality, " he said.

"The paramount idea behind this exhibition is to illustrate the best-known facets of her life, but also to show all the parts of it we no longer think about but that make her even more engaging and human."

Prince Albert II of Monaco added that the show would "revive happy memories we shared with our mother."

"This is a very emotional and proud moment for me, knowing that a tribute is being paid to our mother, " he said.