• Pippa Middleton welcomed her third child, daughter Rose, with husband James Matthews in June
  • Kate Middleton has met her youngest niece and thinks the newborn is "gorgeous," a report says
  • Pippa is reportedly "doing well" since delivering her daughter

Kate Middleton has met her new niece.

News broke earlier this month that Pippa Middleton and her husband James Matthews welcomed their third child — a baby girl — in the Lindo Wing of St. Mary's Hospital in London in June.

This week, an unnamed source told Us Weekly that the Duchess of Cambridge has "already met" Pippa's newborn daughter, noting that Kate thinks her niece is "just gorgeous."

Kate — who shares Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4, with Prince William — is reportedly "overjoyed for her sister" and brother-in-law, according to the insider.

Pippa and Matthews are also parents to son Arthur, 3, and daughter Grace, 16 months. They named their second daughter Rose, according to the outlet.

"Pippa is doing well since giving birth to Rose," the source told Us Weekly. "She and James are absolutely infatuated with their bundle of joy and are adapting well to being parents of three."

News of Pippa's third pregnancy broke last month shortly after she debuted her baby bump while attending the "Platinum Party at the Palace" in London on June 4.

During the Platinum Jubilee event, which honored Queen Elizabeth II's 70 years on the throne, Pippa wore a green, long-sleeved dress that showed off her growing bump.

Kate and Pippa share a close bond, and their tight connection has been evident. When the Duke and Duchess of Cambridge welcomed their only daughter, Charlotte Elizabeth Diana, in May 2015, Kate included a nod to her sister, whose middle name is Charlotte, along with references to Prince William's grandmother and his late mother Princess Diana.

Pippa returned the favor by naming her eldest daughter, Grace Elizabeth Jane. Elizabeth is Kate's middle name.

In an interview with "Today" in 2014, Pippa said that her relationship with her sister didn't change even after Kate joined the royal family. She shared that though Kate was under a lot of "pressure" with her role in the Firm, they still "do a lot together as a family."

"I think that's really the heart for all of us is having a really close family that we can sort of be normal with each other, treat each other normally. And that's sort of kept us all, you know, affixed to the ground," Pippa said.

Asked if she could still call her older sister anytime, Pippa said, "Yeah, we do. We have a very normal, sisterly relationship. We're very close. And, you know, we support each other and get each other's opinions and things."

Pippa Middleton, Kate Middleton
Pippa Middleton may not choose Kate Middleton as her son's godmother. Pictured: Middleton sisters react while watching the action from the Royal Box of the men's singles final match between Britain's Andy Murray and Switzerland's Roger Federer on Centre Court on day 13 of the 2012 Wimbledon Championships tennis tournament at the All England Tennis Club in Wimbledon, southwest London, on July 8, 2012. Getty Images/Leon Neal/AFP