Pippa Middleton is officially a mom!
The 35-year-old younger sister of Kate Middleton gave birth to a baby boy on Oct. 15 at 1:58 p.m., weighing 8 lb and 9 oz, her rep tells ET.
“Everyone is delighted and Mother and baby are doing well,” the rep's statement reads.
Meanwhile, Kensington Palace tells ET, "The Duke and Duchess of Cambridge are thrilled for Pippa and James."
Pippa married Matthews last May. This marks the first child for both.
Pippa confirmed she was pregnant in June, when she wrote a guest column for U.K. supermarket monthly, Waitrose Kitchen magazine.
“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, adding that she kept her pregnancy a secret until the "riskier months" were over.
She specifically talked about working out while pregnant given her passion for fitness.
“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 on what you can and can’t do,” Pippa wrote. “And this being my first pregnancy, I had so many questions I felt were still unanswered.”
“So I decided to use my own initiative and adapted my current exercise routine, adjusting the weight and intensity to what felt right for me,” she continued. “I work out for 45 minutes, three to four times a week depending on my energy levels, but ensured that the routines I did were lighter than usual. 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 favorite jeans will still fit eventually!"
Pippa also took a page out of her idol Serena Williams' playbook.
“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 wrote in her column later that month. "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.”
“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,” Pippa added.
In July, she showed off her baby bump at her nephew Prince Louis' christening. Most recently, Pippa attended Princess Eugenie's wedding to Jack Brooksbank on Sept. 13 at Windsor Castle, sporting a chic long-sleeved green dress and black heels.
Meanwhile, it's definitely a busy time for the royals when it comes to baby news. On Monday, Kensington Palace announced Meghan Markle is pregnant with her first child with Prince Harry. The two will welcome their baby in spring 2019.
For more on Pippa's pregnancy, watch the video below:
Pippa Middleton Shares Her Go-To Pregnancy Workout as She Enters Third Trimester
Pippa Middleton's Printed Dress Proves the Voluminous Sleeve Trend Isn't Going Anywhere -- Shop Her Look!
See Pippa Middleton's Growing Baby Bump in a Chic Striped Shirt Dress -- Shop Her Look!