Rare Photos of Grace Kelly and Prince Rainier

Before Kate and William, and before Diana and Charles, there were Grace and Rainier.

In 1956, Hollywood royalty Grace Kelly – already beloved from her work in Alfred Hitchcock’s Rear Window and an Oscar winner for The Country Girl, married Rainier III, Prince of Monaco, to become real royalty as the Princess of Monaco.

As the world waits just 10 more days for the largest-scale royal wedding ever, 55 years ago Kelly, then 26, set the bar extravagantly high for royal “I Dos.” The golden-haired actress wore a wedding dress designed by award-winning M-G-M costumer Helen Rose, which had been labored over for six weeks by the hands of three dozen seamstresses.

With 600 guests in attendance – including luminaries-of-the-day screen stars Ava Gardner and Gloria Swanson and hotelier Conrad Hilton – and an additional 30 million viewers tuning in at home, the wedding was certainly the actress’s most-watched role ever. Fortunately, LIFE magazine captured it all from behind closed dressing room doors, beneath balconies and across the hushed aisle.

To commemorate the 55th anniversary of the marriage of Grace and Rainier, LIFE has also released an intimate gallery featuring the publication’s coverage of the 1955 wedding.

The venerable title has also released an assortment of previously unpublished portraits of Grace Kelly before she became the Princess of Monaco. All shots were taken by celebrated photographer Loomis Dean from 1953 to 1954.