Pippa Middleton is talking about her son, Arthur, for the very first time.

The younger sister of Kate Middleton recently revealed that the six-month-old baby loves swimming and he's getting better at it every day.

“Starting my son, Arthur, swimming at four months old has given him confidence and enjoyment in water,” she told Waitrose Kitchen magazine.

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“He’s now six months old, and swimming is one of our favorite activities. The exercise helps guarantee sound daytime sleeps, and the movement has improved his digestion," she added.

Middleton welcomed Arthur in October 2018 and swam throughout her pregnancy.

“From personal experience, I’d confidently say I find it has been the most enjoyable and rewarding form of exercise since I found out I was expecting,” she previously shared with the UK supermarket magazine.

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“It’s comforting to know that it’s safe throughout pregnancy, and you don’t need to adapt and change too much (unlike most other sports). It’s so good for you that you could swim every day – as long as you don’t overexert yourself – right up until the end of the third trimester.”

Arthur is the first child for Middleton and her husband, James Matthews, who she married in May 2017.