Chelsea Davy and Prince Harry’s seven-year relationship came to an end after attending the wedding of Kate and Will, according to a new book.

The couple had been dating on and off since 2004 after meeting at school, but their relationship was far from smooth sailing.

They finally agreed to call it quits in 2011, but remain close friends with Chelsea even attending Prince Harry's wedding to Meghan Markle in May.

The book claims that the wedding of Harry's brother, William, is said to have been what convinced Chelsea once and for all that Harry wasn't the one.

Harry took Chelsea as a plus one to the lavish affair at Westminster Abbey, London on April 29, 2011, in the hope of rekindling their romance.

But the wedding, watched around the world, apparently made Chelsea realise a life by the side of a high-profile member of the royal family wasn't for her.

According to a Royal Insider, writing in Royal Biography Harry, Conversations with the Prince, journalist Angela Levin said, a friend revealed that seeing the enormity and pomp of the day convinced Chelsea that she and Harry had been right to separate.

Although they had a lot in common, she saw clearly that because they came from such different worlds, it could never have worked, especially as she valued her privacy and guarded it so carefully.

Harry is also said to have read his best man's speech over the phone to Chelsea, who a few years ago swapped a career-in-law to run her own jewellery business.

Miss Levin added, Harry had read it out at first over the phone to Chelsea in South Africa, who despite no longer being his steady girlfriend, has also been invited to the wedding.

She suggested he remove some of the racier anecdotes, including a reference to Kate's colour legs, as she didn't think the Queen would take kindly to lattish humour.

Chelsea, the daughter of a South African safari farmer, was born in Zimbabwe.

Her mother is a former Coca-Cola model.

She attended Charlton Ham College before moving to Stowe School in Buckinghamshire, where she met Harry.

But she is said to have never enjoyed the publicity or pressure that came with the high-profile romance.

She previously told The Times, It was so full-on, crazy and scary and uncomfortable, I found it very difficult when I was bad.

I couldn't cope.

I was young, I was trying to be a normal kid and it was horrible.

After Harry's wedding to Meghan, Chelsea was seen locking lips with her TV producer boyfriend James Marshall during a romantic lunch, and they didn't appear to care who was watching.

The love app display came just days after it was reported Chelsea and Prince Harry had an emotional phone call before he wed Meghan.

In the days before the wedding, Harry and Chelsea had a tearful parting phone call.

A source told Vanity Fair that it was their final call, a parting call in which they both acknowledged Harry was moving on.

Chelsea was quite emotional about it all, she was in tears and almost didn't go to the wedding.

Despite the end of their romantic relationship, Chelsea and Harry have remained close friends.