While on a train to the French Riviera, fellow passenger Olivia de Havilland relayed an offer from her then-husband, Pierre Galante, to escort Kelly to a meeting with the Prince, accompanied by the editor-in-chief of Paris Match, Gaston Bonheur.

[5] Due to a power shutoff as a result of a workers' strike in Cannes, Kelly styled herself in a no-iron, wrinkle-free floral McCall's dress pattern, with her still-wet hair in an updo with flowers.

Their meeting was photographed at the Palace, with Rainier and Kelly subsequently taking a tour of the residence, which included the private zoo that belonged to the Princely Family.

Upon the start of filming High Society later that month, Rainier presented her with a second diamond engagement ring made by Cartier to wear during production, in the place of a prop.

[12] Two weeks before her wedding, Kelly sailed from New York to Monaco on the SS Constitution with 65 family and friends, and was greeted by 20,000 Monégasque residents upon arrival.

[14] Following the widespread coverage of their engagement, brands such as Max Factor falsely claimed that they would create the cosmetics used on her wedding day, with hosiery-maker Willy's de Mond stating that they would craft custom pearl-trimmed stockings for the bride, both of which were denied by Kelly's representatives.

[22][16] On April 19, 1956, the church ceremony was held at the Saint Nicholas Cathedral, with the Solemn Pontifical High Mass conducted in French by the Bishop Gilles Barthe, in the presence of 700 guests.

[23][18] A reception at the Hotel de Paris was held for 600 guests and 3,000 Monégasque citizens, with a six-tiered wedding cake replicating the Prince's Palace in sugar, which was cut with Rainier's ceremonial sword.

[25] Rainier later remarked that the celebrations were "the biggest circus in history" and that the couple had "both agreed that we should really have got married in a little chapel in the mountains.”[16][17][14] For the civil ceremony, which was held at the baroque throne room of the palace on 18 April 1956, the dress worn by Kelly was made of pale pink taffeta, covered by cream lace, designed as a high-necked, fitted dress with a flared skirt.

The dress was designed with lacing at the high-necked-collar, with the detail extending to the long sleeves, as well as a fitted waist panel, which gave way to a lengthy, billowing skirt.

[citation needed] The bride's sister, Margaret Davis (later Conlin), was matron of honour, with Judy Balaban, Rita Gam, Maree Frisby, Carolyn Scott, Sally Parrish, and Bettina Thompson serving as bridesmaids.

[30] The bridegroom's attendants included Count Charles de Polignac, Lieutenant Colonel Ardant, and John Kelly Jr., brother of the bride.

[33][34] Prince Rainier and Princess Grace departed after their wedding for a seven-week Mediterranean honeymoon cruise on their yacht, Deo Juvante II.