The 34-year-old, who is expecting her first child with husband James Matthews, attended the fourth day of the 2018 Wimbledon Championships on Thursday, turning heads in a chic white sundress that's perfect for summer.
The younger sister of Kate Middleton arrived to the tennis tournament with her brother, James, rocking a lace Anna Mason dress with ruffled sleeves.
She completed the look with ankle tie wedges, a J. Crew clutch and round-framed Chanel sunglasses.
Inside the All England Lawn Tennis Club, the Middletons sat centre court to watch Spain's Rafael Nadal play Kazakhstan's Mikhail Kukushkin in their men's singles second round match. And judging by the pics, it appears they were highly entertained!
"I've been a tennis fan since childhood, as a player and spectator, and have been keen to continue playing safely throughout my pregnancy," she explained. "Take Serena Williams. She famously proved that women can play a high level of tennis from two months (when she won the 2017 Australian Open) up to eight months."
She continued, "Few of us can relate to this elite excellence, but if you’re a healthy, well-trained player with an uncomplicated pregnancy there’s no reason why you can’t continue a good level of tennis."
Earlier this week, a royal source told ET that Meghan Markle also has plans to cheer on Williams at the tournament.
The tennis pro spoke about the possibility of having the Duchess of Sussex make an appearance at one of her matches following her first round win against Dutch tennis player Arantxa Rus on Monday.
"I don't know, we'll see," she said. "If I keep winning."