Around 11:45am the pair said 'I do' and loud applause and cheers were heard as the happy couple stepped out as man and wife.
The couple were surrounded by close family and friends and their Boston Terrier dog Daphne as they said their vows in the grounds of the Prince's Palace, as a picture shared by the couple shows.
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The bride kept true to her style and wore a hippie chic bridal gown by Missoni. She wore silver flat sandals and let her glossy brunette locks loose which she adorned with a simple floral headpiece.
The groom chose a dark blue suit with a spotted tie and white shirt.
The mother of the groom, Princess Caroline, wore a stunning knee-length red dress, thought to be by close family friend Karl Lagerfeld, her designer of choice for special occasions.
Pregnant Charlotte Casiraghi chose a light blue transparent dress which highlighted her growing baby bump and Princess Charlene wore an all-white ensemble, which perfectly matched Prince Albert's tie.
Following the ceremony, Andrea and Tatiana were joined by their 400 guests for an al fresco lunch next to the pool at the Prince's Palace. Among the elite guest list were the likes of Greek shipping heiress Eugenie Niarchos, the Missioni fashion family and Tatiana's influential New York-based siblings.
Six barrels of beer straight from the Brasserie de Monaco have also apparently delivered for the celebrations.
The ceremony was a relatively simple affair by royal standards although obviously the groom's position as second in line to the throne after his mother meant that the ocassion came with some fanfare.
Tatiana pictured with her friends at her pre-wedding dinner
No official information was issued about details of the wedding, except to confirm that it was taking place. This was at the express desire of the notoriously private couple, who are parents to a baby son named Sacha.
A special place in the bridal party was reserved for Charlotte Casiraghi, the groom's sister, who introduced the pair. The royal beauty, who is thought to be about six months pregnant, attended with her partner French screen heartthrob Gad Elmaleh.