Pippa Middleton shares her go-to pregnancy workout

Pippa Middleton continues to stay in shape while entering her third trimester.

The 34-year-old expectant mother -- and Kate Middleton's younger sister -- gave an update on how she's feeling as she gets ready to welcome her and husband James Matthews' first child together. In her latest column for the U.K. supermarket monthly Waitrose Kitchen magazine this week, Pippa reveals that her recent go-to exercise regimen consists of swimming.

"Swimming throughout pregnancy offers a wonderful feeling of weightlessness," Pippa writes. "As the months pass, you feel heavier by the day, but being in water gives that floating, light-as-air feeling that soothes and relieves the body, counteracts increased back strain and stretches the legs from the growing bump. It’s non-impact, gentle and relaxing."

What the brunette beauty, who's been rocking the perfect summer maternity style lately -- loves most about this form of exercise is that it's one of the safest, she explains.

"You don’t need to adapt and change too much (unlike most other sports)," Pippa continues. "It’s so good for you that you could swim every day -- as long as you don’t overexert yourself -- right up until the end of the third trimester."

The Duchess of Cambridge's little sis confirmed she was expecting back in June, revealing that she hadn't had any setbacks in the first three months. “I was lucky to pass the 12-week scan without suffering from morning sickness. That meant I was able to carry on as normal,” Pippa wrote in the same magazine, adding that she kept her pregnancy a secret until the "riskier months" were over.

Since then, Pippa has been spotted enjoying family time at Prince Louis' christening and attending Wimbledon with her hubby last month. See more on her pregnancy in the video below.

See more of the mom-to-be below!