The 34-year-old sister of Catherine, Duchess of Cambridge, was rumoured to be pregnant with her first child with husband James Matthews, and she has now officially confirmed the happy news.
Pippa made her confession while adding that she's been lucky enough to avoid the severe morning sickness that her older sister - who has Prince George, 4, Princess Charlotte, 2, and Prince Louis, 1 month, with her husband Prince William - suffered during her three pregnancies.
She revealed: "I was lucky to pass the 12-week scan without suffering from morning sickness. That meant I was able to carry on as normal.
"When I learned the happy news that I was pregnant I realised I needed to adjust my 4 to 5-day-a-week routine.
"I've noticed my body change but through exercise I feel it's being strengthened. I'm fanatical about sport and have looked at loads of books and websites on exercise during pregnancy but have been disappointed by the limited technical information what you can and can't do."
The brunette beauty also admitted she still has "so many questions" about whether or not she is able to exercise while pregnant, as she's keen to maintain her figure for as long as possible.
She added to Waitrose Kitchen magazine: "This being my first pregnancy, I had so many questions I felt were still unanswered. I wanted to know things like, would I strain if I served in tennis, are strokes of swimming safe, can I still do a normal yoga class if I avoided certain positions? Could I still work my abs?
"I've noticed my body change and weight increase, but through effective exercise and sports I feel that it's been strengthened to support a healthy pregnancy, birth and recovery … And ensure that post-baby, my old favourite jeans will still fit eventually!"