Tennis whites may be compulsory on the court but Pippa Middleton proved that it is anything but for the spectators as she arrived for day eight of Wimbledon on Monday in a vibrant Sixties-inspired minidress.

Heading into Centre Court's Royal Box, the Duchess of Cambridge's sister stood out for all the right reasons in the geometric print A-line mini dress by British designer Tabitha Webb.

Middleton teamed the tangerine and dove grey print dress with soft suede midi courts and a pale leather clutch bag as well as a pair of classic Clubmaster-style sunglasses. Tabitha Webb is a favourite of Pippa's and she has been seen in the West London-based designer's dresses before.

Pippa Middleton at Wimbledon
Pippa Middleton at WimbledonGetty

Whilst Pippa's vibrant Tabitha Webb design is no longer available, there are similar styles available on her website in lace for £350.

Pippa Middleton at Wimbledon
Pippa MiddletonGetty

Joining Pippa for the Roger Federer vs Steve Johnson match on Monday was US Vogue Editor Anna Wintour who eschewed Paris Haute Couture week for a seat at the heart of the sporting action in SW19. Wintour is a known Wimbledon enthusiast who attends every year and could be seen cheering and clapping for Federer as she joined the tennis player's wife Mirka in the Royal Box, sat just in front of Pippa Middleton.

Also in a bold artistic print, Wintour and Middleton thoroughly brightened up what had turned into a rather dull, overcast afternoon, although true to form, Wintour did not remove her sunglasses throughout the match.

Anna Wintour (left) in the Royal Box
Anna Wintour (left) in the Royal BoxGetty

The group had a great result though as seven-time champion Roger Federer went through to the Wimbledon quarter-finals after beating Steve Johnson 6-2 6-3 7-5. Federer's next challenge will be 2014 US Open champion Marin Cilic as the 34-year-old seeks to win a record-breaking eight men's singles titles.