Pietersen, who lives with his wife Jessica close to where William and Kate were spotted on Saturday, took to social media to hit back at the “ridiculous and cruel” people who write up “wild” theories about the “humble” royals.
He wrote on X: “The conspiracy theories around Kate are absolutely absurd! We see Will & Kate most days and in the last couple days too!
“It beggars belief that people would be so ridiculous and cruel in writing B******* on this platform that are out and out lies! Will & Kate are the most wonderful parents and as normal/humble as they come.”
Pietersen urged people “leave her and her beautiful family alone”.
He added: “Let Kate who is recovering from an operation recover. Leave her and her beautiful family alone!!!!”
The former cricket star also tagged Kensington Palace in the tweet.
It comes as Express.co.uk revealed the Princess of Wales has found an unlikely recovery companion in the guise of Pietersen’s wife and former Liberty X singer Jessica.