Pippa Middleton reportedly pregnant with her first child

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

RELATED: Here's a look at the British royal family's net worths: 

10 PHOTOS
The British royal family net worths
See Gallery
The British royal family net worths

Kate Middleton Net Worth: $6 Billion

Photo credit: Press Association

Princess Charlotte Net Worth: $3.8 Billion

Photo credit: Press Association

Prince George Net Worth: $3 Billion

Photo credit: Press Association

Queen Elizabeth II Net Worth: $550 Million

Photo credit: Reuters 

Prince Charles Net Worth: $100 Million 

Photo credit: Getty 

Prince William Net Worth: $40 Million

Photo credit: Getty 

Prince Harry Net Worth: $40 Million

Photo credit: Press Association

Prince Philip Net Worth: $30 Million

Photo credit: Press Association

Camilla Parker Bowles Net Worth: $5 Million

Photo credit: Press Association

Meghan Markle Net Worth: $5 Million

Photo credit: Press Association

HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

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.

More from ET Online: 
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 Liv

Read Full Story