KATE'S SECRET DINNER WITH HARRY'S EX

THE DUCHESS CALLS ON CHELSY DAVY FOR A HUGE FAVOUR!

For Prince Harry, Chelsy Davy was always the one that got away. But spare a thought for the Duchess of Cambridge, who was also incredibly close with her brother-in-law's long-term girlfriend – and was said to be “absolutely devastated” when the pair broke up for good in 2011.

“Kate and Chelsy were thick as thieves," shares a source. "They always attended events together when they were dating William and Harry.”

As they navigated the choppy waters of royal life, Chelsy and Kate were often seen sticking to each other like glue at parties, weddings, and polo matches, preferring to enjoy their own company rather than spending too much time with the “society snobs” that attended these events.

“At the time, Kate quietly thought Harry made the biggest mistake of his life in letting her go,” says the source.

Despite Chelsy, now 36, ending things with Harry, insiders say she has remained on good terms with Kate, 40.

"They've stayed in touch over the years," says our source. “Kate was delighted to see Chelsy at Harry's wedding. And given things were already tense with [his bride] Meghan Markle, she must have had a tinge of wistfulness about what could have been if he'd married Chelsy."