Duke and Duchess of Cambridge Enjoy Rare Night Out on Mustique Holiday

The Duke and Duchess of Cambridge have been enjoying a well-deserved family holiday in Mustique.

The couple, who have three children under the age of five, were spotted on a rare night out at the island's famous Basil's Bar.

William and Kate attended the party, which was also attended by Mick Jagger and his daughter Jade, on the early side and looked to be having a great time.

The theme of the bash was a splash of gold, and fellow revellers have exclusively revealed to Hello magazine that the royal couple attended the party and enjoyed some special alone time during their family holiday.

The Duke and Duchess are good friends with legendary barman Basil Charles of Basil's Bar, who even set up a pop-up bar at the Goring Hotel in London, where Kate stayed the night before her wedding.

During the week of their nuptials in 2011, the Cambridges visited Mustique for the first time and have been returning ever since.

This is officially the Cambridges' first holiday as a family of five, with Prince Louis joining his big brother Prince George, who turned five in July in Mustique, and Princess Charlotte, who turned three in May.

While the couple enjoyed a rare night off parenting duties at the beach side, it is thought that the doting grandparents, Carol and Michael Middleton, stayed home with their three young children.

Given the complete privacy of the exclusive island, it comes as no surprise that William and Kate take the opportunity to blend in with other tourists.

With a no-fly zone in Forest over Mustique and the discretion of other guests, the royals are able to truly relax and let their hair down.

On previous trips, they have played tennis, gone snorkelling and scuba diving, and enjoyed cocktails at the five-star Cotton House Resort.

Martin Katz, a famed Beverly Hills jeweler, and his wife Kelly met the royals in 2008, and speaking exclusively to Hello!

magazine in 2015, Kelly revealed, “they're quite the sportsmen.

We went diving and they went very deep, more than 90 feet.

Our instructor said Martin and I weren't qualified to go on the shark dives they went on.

Kate looked very casual, she wasn't particularly wearing makeup, she looked lovely,” said Martin.

“She just couldn't be more gracious and talk to everybody who would talk to her.

It wasn't like she was working the room, but if someone wanted to speak to her, she was happy to speak.

I think what struck me was that they were human like everybody else, dressing to fit in like everybody else.”