Pippa Middleton gives birth to baby boy

The Duchess of Cambridge's younger sister Pippa Middleton has given birth to a baby boy.

The 35-year-old socialite and author and her husband James Matthews have welcomed their first child into the world and both mother and baby are doing well.

A representative for the couple said: "Everyone is delighted and mother and baby are doing well."

The baby boy - whose name has yet to be released to the public - was born at 1.58pm on Monday (Oct 15), weighing 8lb and 9oz (3.88kg), the same place where her sister Kate gave birth to her three children.

Pippa Matthews (Middleton) leaves the wedding of Britain's Princess Eugenie of York to Jack Brooksbank at St George's Chapel, Windsor Castle, in Windsor, on October 12, 2018.Photo: AFP

Pippa sparked speculation she was due to give birth any time soon when she was spotted heading into the Lindo Wing on Monday. Pippa confirmed she was expecting her first child back in June.

She revealed: "I was lucky to pass the 12-week scan without suffering from morning sickness. That meant I was able to carry on as normal.

"When I learned the happy news that I was pregnant I realised I needed to adjust my four to five-day-a-week routine. I've noticed my body change but through exercise I feel it's being strengthened. I'm fanatical during pregnancy but have been disappointed by the limited technical information what you can and can't do.

"This being my first pregnancy, I had so many questions I felt were still unanswered. I wanted to know things like, would I strain if I served in tennis, are strokes of swimming safe, can I still do a normal yoga class if I avoided certain positions? Could I still work my abs? 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 favourite jeans will still fit eventually!"