Pippa Middleton, sister of Catherine, Du

Pippa Middleton, sister of Catherine, Duchess of Cambridge, watches Jo-Wilfried Tsonga of France play against Roger Federer of Switzerland during the singles final on day eight of the ATP World Tour Finals tennis tournament in London on November 27, 2011. Roger Federer won a record sixth ATP World Tour Finals title with a 6-3, 6-7 (6/8), 6-3 victory over France’s Jo-Wilfried Tsonga on Sunday. With this win he moved ahead of Pete Sampras and Ivan Lendl on the list of Tour Finals champions in the 100th final of his majestic career. The 30-year-old, who retains the title he won 12 months ago, has now won 70 trophies in his career and has also equalled Lendl’s record of 39 match wins in the end-of-season event. AFP PHOTO / GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)