The 27-year-old fashion designer has a penchant for vintage clothing — and Olivier, who is the half brother of former French president Nicolas Sarkozy, certainly knows this as he reportedly proposed with an intricate Cartier diamond and sapphire ring.
Inside story on Mary-Kate Olsen's huge vintage engagement ring
Mary-Kate and her sister Ashley are known for their trademark style, and tend to wear specific cuts, colours and styles — 1920s inspired dresses, tops with long, flowing sleeves, suits with on-trend capes and V-neck cut garments.
Scroll down for our predictions on what Mary-Kate Olsen may wear on her wedding day...
Mary-Kate may ditch the white and choose a colourful number, like these Valentino autumn/winter 2014/2015 dresses which focus on transparent chiffon, silk tulle and bird and floral-embroidery.
Temperley London's winter bridal collection features flowing skirts which cascade down the back, feminine jackets with embroidered lining and V-cut necklines with billowing sleeves. wedding dresses online Australia
The Hayley Paige for JLM Couture dresses feature diamond and stone-encrusted necklines and form-fitting chiffon pieces.
A close up of Temperley London's satin and pearl-embroidered neckline.
Jenny Packham's bridal gowns incorporate trademark styles found in Mary-Kate's party wardrobe — covered shoulders and V-necklines. The actress could opt to wear a dazzling evening style gown over a traditional white dress. beach wedding dresses online
A more romantic dress would come from Claire Pettibone's 2014 collection, which showcase empire-style gowns, double layered skirts, vintage lace and floral-embroidered backs.
The bride could choose 1920s-inspired dresses from Pronovias' 2014 collection, which feature feathers, pencil skirts and sheer overlays. wedding dresses 2014
The Hayley Paige for JLM Couture designs also focus on plunging necklines and see-through dresses, while pieces from the Reem Acra winter collection are heavy on the silk and satin and feature diamond detailed nipped-in waists.
Mary-Kate (right) has just got engaged to Olivier Sarkozy, a financial tycoon based in New York. Apart from being an actress and designer, the Olsen beauty has become a style icon in her own right known for her boho chic trademark style.
The Olsen twins are virtually inseparable and are always spotted together at parties or sitting front row at fashion shows. Apart from growing up on television screens, the sisters are also the masterminds behind fashion brand The Row.
This will be Mary-Kate's first trip down the aisle, whereas Olivier has been previously married to Charlotte Bernard and has two children with the writer. Dresses online Australia