Why was Federer at Pippa Middleton's wedding?

Roger Federer had a few fans scratching their heads with his appearance at Pippa Middleton's wedding, but the reason for his attendance has now been revealed.

Roger and Mirka Federer somewhat stole the show ahead of Pippa's wedding to James Matthews on Sunday.

The Swiss tennis ace and his beautiful wife were captured by photographers walking to the service, looking extremely happy and handsome.

Image: Getty

It has since emerged that Pippa is a huge tennis fan and met Federer at Wimbledon a few years ago.

She is regularly in attendance at the All England Club during the prestigious grand slam and is often spotted at Federer's matches.

Image: Getty

“I first went to Wimbledon when I was eight years old and already a very keen tennis player," Pippa recently said.

“During this first trip I acted on my childish tennis dreams and bought myself a postcard of the women’s championship trophy, on which I wrote, ‘I will win this one day,’ with my signature below."

Image: Getty

They reportedly struck up a friendship and have stayed in attendance ever since, including an interview Federer did for Vanity Fair while Pippa worked there.

The tennis connection also explains Tim Henman's invitation to the wedding - a former world No.4 from England.

Federer recently announced his intention to skip the upcoming French Open to focus on his favourite surface at Wimbledon.

He hasn't played on the ATP tour since winning the Miami Open in March, his third title of 2017.