How sweet! Now that Pippa Middleton is pregnant with her first child and friends think Kate Middleton is pregnant with her fourth, the sisters are turning to each other for expert mom advice.

"They confide in each other about everything," a source told Life & Style. "When they were younger they'd always share stories about boys and school life. Now they’re sharing pregnancy stories!"

Kate, who is already a mom to sons Prince George, 4, and Prince Louis, 2 months, and daughter Princess Charlotte, 3, is also helping her younger sister out with decorating her baby's room. "She’s been giving Pippa lots of tips on what’s to come and helping her with the nursery," the source added. "She’s also given Pippa some of George and Charlotte’s hand-me-downs but is obviously keeping some for Louis and her next baby." The insider continued, "Kate and Pippa have had so much fun shopping online for baby clothes and accessories!"

When Kate gave birth to her third royal baby with husband Prince William on April 23, Pippa was one of the first people to meet the family's new addition at Kensington Palace. So, now that Pippa, 34, is expecting her first little one with hubby James Matthews, the Middleton sisters are sure to be over the moon with baby joy! "Kate has so much knowledge to share," a friend of the siblings recently revealed to Us Weekly. "She’s a walking baby encyclopedia at this point!"

kate and pippa

The news of Pippa's pregnancy first broke on April 21. "When Pippa found out she was pregnant, she was obviously thrilled and utterly overjoyed," a source revealed to The Sun. "Naturally, big sister Kate and [her] parents, Carole and Michael [Middleton], were the first people she told — James aside — and they could not have been more delighted."

Then, just weeks after Pippa showed off her baby bump at the royal wedding and the French Open in Paris, the socialite confirmed she's expecting baby No. 1 on June 7. "I was lucky to pass the 12-week scan without suffering from morning sickness. That meant I was able to carry on as normal," she wrote in her weekly column in Waitrose Kitchen Magazine. "When I learned the happy news that I was pregnant I realized I needed to adjust my 4 to 5-day-a-week [workout] routine. 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 middleton getty images

Shortly after Pippa and James' lavish May 2017 wedding, a royal insider told Life & Style that the couple was eager to start a family. "They are trying for a baby, and Pippa might already be expecting. I know she would love to be pregnant at the same time as Kate," the source said at the time. "She would love to have a boy first and then a girl. She wants three children." We're so happy for the sisters!

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