One year ago, Paul Burrell predicted that Prince William and Kate Middleton would get married in the summer of 2011. Princess Diana's former confidant got it right thanks to his insider's knowledge of how the royal family works.

For more than 15 years Burrell worked for the royal household, first as the Queen's footman and then as butler to Diana, Princess of Wales. 

In his only Canadian interview with Canada AM, Burrell reminisced about the late princess and shared his thoughts about this week's historic marriage of Prince William to Kate Middleton.

"I think Diana would have loved Kate. I think she would have loved her to death because all she wanted for her boys was something she never had -- a happy marriage," Burrell, 52, told Canada AM co-host Beverly Thomson.

Burrell also offered these words of advice to future princess, Middleton.

"Be careful what you wish for," Burrell said. "The minute she walks out of Westminster Abbey as a princess her life will change completely."

During his time in royal service, Burrell saw how the realities of royal life impacted Princess Diana, who was only 20 when she married Prince Charles in a fairy-tale wedding in 1981 at London's St. Paul's Cathedral.

Sadly, that fairy tale was short lived.

Diana's marital unhappiness and other royal secrets were revealed by Burrell in this 2003 tell-all, "A Royal Duty". The book was written, so Burrell claimed, to defend Diana. But that explanation did not wash with Diana's sons, William and Harry.

The princes issued this statement when "A Royal Duty" first hit bookstands: "We cannot believe that Paul, who was entrusted with so much, could abuse his position in such a cold and overt betrayal…It is not only deeply painful for the two of us, but also for everyone else affected and it would mortify our mother if she were alive today."

Burrell responded to the princes' criticisms during a television interview, telling the young royals to "grow up." He also said that the boys were being manipulated by the system.

Diana wasn't prepared for royal life, Kate is

By Burrell's account, the signs were there from the start of Diana's engagement to the Prince of Wales that her life would not be her own.

Before the couples' engagement was officially announced, Burrell said that he remembered the day that the crown jeweler arrived at the palace with his attaché case. The case was filled with a selection of royal engagement rings. After Queen Elizabeth II and Prince Charles perused the rings, Burrell was sent to bring Diana into the room.

According to Burrell, Diana later said these words to him about her engagement ring: "I think it's a bit big, a bit gaudy."

"There's a myth surrounding that ring," said Burrell, who was shocked when he learned that it had become Middleton's engagement ring.

"That ring symbolized more than a piece of jewellry.... It symbolized a love Diana had for Prince Charles, which wasn't reciprocated," said Burrell.

"Kate will forever wear the ghost of Diana on her hand."

Burrell also described Diana's earliest days in the palace as lonely ones.

"She was almost locked away. They didn't take care of her in the early days," said Burrell.

According to Burrell, Diana used to call up her staff just to have people come and talk to her. Burrell was also sent out on runs to McDonald's just to pick up some regular commoner food for the princess.

By contrast, Middleton is entering into her royal marriage under very different circumstances.

"Kate has had eight years to get used to the royal family. Diana didn't have that," said Burrell, who will report on this week's royal wedding for Fox News.

"Diana was 18. She was shy, naïve, and immature in lots of ways. She's attacking this (marriage) like a business and so she should."

Even though Middleton has had more time to assimilate into royal life, she will still have to sink or swim once she becomes part of the family business.

"Look around Kate. This firm, this system that's been around for 1,000 years isn't going to change that much," said Burrell.

He also offered this last bit of advice to the happy couple about their wedding.

"I would say to William enjoy it if you can…Remember it's yours and Kate's day above everything. It's the day you're getting married."