Middleton, 38, and her husband James Matthews, 46, are expecting their third child together. She was at the event Saturday honouring Queen Elizabeth II's Platinum Jubilee.
Pipa Middleton has 2 Children
The couple has a 3-year-old boy named Arthur and a 1-year-old daughter named Grace. They married in 2017.
Pipa Middleton stunned in green dress
Fans reacted to a happy photo of the 38-year-old journalist, who wowed in a green gown at the Queen's Platinum Jubilee Party, on social media.
Pipa Middleton and James relationship over the years
In the midst of the excitement and speculation, look back at Pippa and James' relationship throughout the years...
Love at First Sight
In 2007, Pippa met Spencer Matthews' brother James, the star of Made in Chelsea, on one of the world's most gorgeous Caribbean islands.
After 5 years of dating
After that, things went quiet until Pippa was caught looking cosy with stockbroker Nico Jackson in February 2013, putting an end to their fledgling affair.
Pipa Middleton dated with Nico
Between 2013 and 2015, Pippa and stockbroker Nico dated. The couple was rumoured to be on the approach of getting married, but in October 2015, they called it quits.
The reunion of James and Pippa
Pippa and James returned to St Barts for a romantic vacation in January 2016, and later made their public debut as an official couple.
James proposes the marriage.
And word of their engagement splashed across the UK in July 2016, just a few months after they announced their romance.
James proposes with a diamond ring
With what can only be described as a massive diamond ring, James proposed over a mini-break to the Lake District.
James and Pipa's Marriage
Pippa looked stunning in a high-neck Giles Deacon wedding gown as she married James at St Mark's Church in Englefield, Berkshire.