The Monegasque royal, 30, will marry her husband Andrea Casiraghi for a second time on 1 February. For her winter wedding, Tatiana will most likely ditch her trademark boho-chic look in favour of a formal, show-stopping Valentino gown.
The Italian dress-maker came out of retirement especially to design his close friend's wedding gown, much like he did when he created Princess Madeleine of Sweden's dress for her nuptials last year.
Queen Máxima of the Netherlands also chose the 81-year-old designer to make her gown, in a style that was strikingly similar to the one he fashioned for Princess Marie-Chantal of Greece seven years before.
Other celebrity brides who have tied the knot in a custom-made Valentino include Anne Hathaway, Courteney Cox and Jennifer Lopez.
Click on the photo above to see royal Valentino dresses.