Pippa Middleton has given birth to her second child.

Pippa Middleton

Pippa Middleton

The 37-year-old socialite and author - who is the younger sister of the Duchess of Cambridge - has welcomed a baby girl, called Grace Elizabeth Jane, into the world with her husband James Matthews.

It has been reported that the baby was born at 4.22am on Monday March 15 and weighs 6lbs 7oz.

A family source told HELLO! magazine of the new arrival - who is a sister for the couple's first child, Arthur, two: "Mother and baby are doing well. She's perfect, everyone is overjoyed at such a happy arrival."

Whilst Pippa did confirm she was expecting her first child, Arthur, she has never officially announced that she was pregnant with the couple's second child.

Meanwhile, Pippa previously praised her "local baby gym" as a "saving grace" whilst raising her son.

Speaking in September 2019, she said: "Now that Arthur is 11 months old and more mobile, I have been trying to come up with different activities to do with him. I needed to find something more than just park walks in the pram. Our local baby gym has been a saving grace. It’s a big space full of fun, soft objects, play mats, stairs, balls, swings, mini trampolines and more to stimulate and physically engage babies and toddlers ... Arthur burns lots of energy in this safe environment and learns many physical skills. I have also noticed him building his confidence with each visit."

At the time, Pippa also revealed she was teaching Arthur to swim.

Speaking when the tot was six months old, she said: “Starting my son Arthur swimming at four months old has given him confidence and enjoyment in water. He’s now six months old, and swimming is one of our favourite activities. The exercise helps guarantee sound daytime sleeps, and the movement has improved his digestion. Water activity is a great form of exercise you can do with your baby."