Miss Middleton was accompanied by her father, Michael, when they pulled up to St Mark’s Church in the quiet Berkshire village of Englefield, shortly after 11.15am.
The bride wore a bespoke Giles Deacon dress, which was crafted to create the impression of being seamless.
The dress was teamed with a Stephen Jones veil, a Maidenhair Fern tiara, and Manolo Blahnik ivory satin shoes.
The groom, brother of former Made In Chelsea regular and reality television personality Spencer Matthews, arrived shortly before the bride.
The couple will say their vows in the picturesque church before a congregation which will include the Duke and Duchess of Cambridge, their children Prince George and Princess Charlotte, Prince Harry and other close family and friends.
The event has seen hundreds of royal fans, press and public descend on the quiet village, near Reading.
Guests included tennis champion Roger Federer and his wife, Mirka, who walked past 100 members of the waiting press and media camped out a short distance from the church.
Pippa’s controversial uncle Gary Goldsmith said hello to the waiting press as he entered, while Princess Eugenie was among the first royals to arrive.