Two Middleton bundles of joy!

Just days before Kate Middleton is expected to give birth to her third child, her younger sister Pippa Middleton is reportedly expecting her first with husband James Matthews, according to The Sun.

The U.K. newspaper reports that Pippa, 34, and Matthews, 42 -- who tied the knot last spring at St. Mark's Church in Englefield -- broke the good news "to close family and friends last week after her 12-week scan." 

The Duchess of Cambridge, 36, was reportedly the second person to find out, following Matthews, and she "could not have been more delighted" for her sister, a source tells The Sun.

ET has reached out to Pippa's rep for comment.

Preparations are already underway for the arrival of Kate's baby with Prince William, as parking restrictions have been put in place outside the Lindo Wing at St Mary’s Hospital in London, England. This is the same private wing where the Duchess gave birth to Prince George, 4, and Princess Charlotte, 2, as well as where the late Princess Diana welcomed both Prince William and Prince Harry.

Kate, who has been lying low as her due date approaches, was spotted casually running errands earlier this month in Swaffham, England. 

For more on the royal pregnancy, watch the video below.

RELATED CONTENT:

Prince William Attends Royal Event as Kate Middleton Awaits Third Baby’s Arrival

Prince William May Have Just Revealed the Gender of His and Kate Middleton's Third Child

Kate Middleton and Prince William Fans Hilariously React to Fake Baby Names on 'Jimmy Kimmel Live'