The brunette beauty and the former cricketer looked like a couple as they arrived hand-in-hand together at Wimbledon on Wednesday, despite reportedly splitting earlier this month.
Pippa - who had been dating Alex for almost a year - looked striking in a red dress teamed with espadrille wedges, while 30-year-old Alex wore a blazer and tie.
The couple sat alongside the 27-year-old beauty's parents Carole and Michael Middleton on Centre Court to watch world number three tennis player Roger Federer take on Jo-Wilfried Tsonga.
Friends had previously claimed the couple separated because Alex was finding it difficult to deal with Pippa's newfound fame since the royal wedding.
One insider said: "Pippa has become very high-profile and it's put a strain on things. They're moving in different circles."
Another insider added: "It is common knowledge in their close circle of friends that Pippa and Alex have recently split up."