The royal Range Rover carrying the Duke and Duchess of Cambridge has left Kensington Palace, en route to St Mark's Church in Berkshire.

As the vehicle whizzed through the palace gates, onlookers got a sneak peek at what Kate Middleton is wearing for the society wedding of the year. As her sister Pippa prepares to put on her Giles Deacon-designed wedding gown (and hopefully enjoys a sneaky glass of pre-wedding prosecco), Kate (35) is already dressed like a princess in a peach outfit and matching fascinator.

Kate Middleton dons a fascinator as she and Prince William head to Pippa Middleton's wedding: https://t.co/TUpGmvzshD #PippasWedding pic.twitter.com/sumtLmL7Zu

— E! Online UK (@EOnlineUK) May 20, 2017

Prince William (33) is looking sharp in a satin waistcoat, stylish tie and sunglasses. Pippa's pageboy and flower girl, Prince George and Princess Charlotte did not appear to be travelling with their parents, but are likely to make an appearance at the church later on this afternoon. Meanwhile Pippa and James' other guests have begun arriving at the church, including tennis ace Roger Federer...

Roger Federer mit Frau zur #PippaHochzeit pic.twitter.com/jM1gAhq1Y5

— Monika Kennedy (@MonBILD) May 20, 2017