Her bateau-necked pure white gown was designed by British designer, Clare Waight Keller, who last year became the first female Artistic Director at the historic French fashion house Givenchy.
Kensington Palace said: "Markle chose to work with her for her timeless and elegant aesthetic, impeccable tailoring, and relaxed demeanour.
"Ms. Markle also wanted to highlight the success of a leading British talent who has now served as the creative head of three globally influential fashion houses – Pringle of Scotland, Chloé, and now Givenchy.
"Ms. Markle and Ms. Waight Keller worked closely together on the design. The dress epitomises a timeless minimal elegance referencing the codes of the iconic House of Givenchy and showcasing the expert craftsmanship of its world-renowned Parisian couture atelier founded in 1952."
The gown was made from a material created by Waight Keller after extensive research in fabric mills throughout Europe. It is an exclusive double bonded silk cady, which Kensington Palace described as being "perfect for the round sculptural look required". The pure white fabric also has a soft matt lustre which was chosen by Markle and Waight Keller as it "brings a fresh modernity to the dress".
"It is beautifully demure, a clean veil with no gathers, and a tiara," says couture wedding dress designer, Phillipa Lepley.
Markle left Cliveden House Hotel, in Taplow, accompanied by her mother Doria Ragland in a vintage Rolls-Royce Phantom IV. The bride-to-be wore a dress created by British designer Clare Waight Keller, the first female Artistic Director at French fashion house Givenchy.
Her wedding ceremony to Prince Harry will take place at midday at the historic chapel at Windsor Castle.
Prince Harry and Markle followed tradition and spent the night before the wedding apart.
He stayed at The Dorchester Collection's Coworth Park in Ascot with his best man Prince William.
Speculation about the dress has been rife ever since the couple announced their engagement on 27 November last year.
The dress reveal is one of the most eagerly-anticipated parts of the wedding day.
During Kate Middleton's marriage to Prince William in 2011, fans were able to catch a glimpse of her now-iconic lace bridal gown as she drove to Westminster Abbey.
The Duchess of Cambridge's dress was designed by Sarah Burton for Alexander McQueen and saw long lace sleeves brought back into fashion again.