Kate Middleton advised by Camilla Parker on how 'to hang on to Prince William' as the future King

Kate Middleton almost saw the end of her relationship with Prince William, had it not been for Camilla Parker Bowles. 

The Duchess of Cambridge was advised by her mother-in-law on how to hold on to the 'busy prince,' as detailed in royal book Battle of Brothers: William, Harry and the Inside Story of a Family in Tumult.

In the book, author Robert Lacey writes how Prince Charles's wife Camilla 'confided in Kate' about how to hang on to a future king.

Mr Lacey begins the chapter 'Kate Not' with a quote from the Duchess of Cambridge on November 17, 2010, following her and Prince William's engagement.

"You go through the good times. You go through the bad times - both personally and within a relationship as well."

"Camilla had confided to Kate the secret of hanging on to a busy prince: fit your timetable - well, basically your whole life - around his," Lacey wrote.

"After St Andrews University, William's timetable was proving rather un-fit-roundable. Marriage had not been included in that schedule."

"While Kate's medium-to-long-term objective was quite simple - to lead William in handcuffs to the altar - for the time being, she had to devise her own independent career path as camouflage," he added.

This is when Camilla came to Kate's rescue and advised her to keep holding on to William with patience.