This is the shocking promise Prince William made to Duchess Catherine's parents which was inspired by Princess Diana

Prince William made a sweet promise to Duchess Catherine's parents when she joined the royal family, according to royal insiders.

It's not surprising that Kate's parents, Carole and Michael Middleton were concerned about how their daughter would cope when she joined the Royal Family.

The Middleton family run a party planning business and had no experience of the public eye until Kate began dating future King William back in 2003.

The couple met when they were both studying at St. Andrew's university.

What promise did Prince William make?

Royal author Phil Dampier revealed, “William gave an assurance to the Middletons that he would always protect her.

“And not let some of the things which Diana endured happen to her.”

Princess Diana’s struggle with life in the public eye is well-known.

She struggled in the months leading up to her wedding to Prince Charles and stepped back from the spotlight for a year between 1993 and 1994.

Sticking to his promise, William released a public statement defending his then-girlfriend Kate back in 2007.

He was angry that photographers had blocked her access to her car on her 25th birthday - and decided to take action.

He and Kate also moved to Wales soon after, no doubt to avoid the mass media attention in London.

Journalist Eleanor Steafel added, “[Kate] tries to make their lives as normal as possible - something William himself promised her parents he would endeavour to do for her when they were married.”

The Duchess of Cambridge’s go-to fashion and beauty buys

Gold Zenyu Chandelier Hoops

(Image credit: Missoma)

Gold Zenyu Chandelier Hoops

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Superga Unisex Adults’ 2750 Cotu Classic Trainers

(Image credit: Amazon)

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From £11, Amazon

Trilogy Certified Organic Rosehip Oil

(Image credit: Amazon)

Trilogy Certified Organic Rosehip Oil