Kate, William and George Will Celebrate Granny Carole Middleton's Birthday in Mustique

It has been nearly a year since Princess Kate walked on a sandy beach.

But, nine months after she, Prince William and Prince George enjoyed the sun and surf of Australia during their tour Down Under, the seven-months-pregnant princess is enjoying a second babymoon with her husband, son and family on the exclusive resort island of Mustique.

It’s been two years since Will, 32, and Kate, 33, then pregnant with George, escaped to the idyllic Caribbean island for their first babymoon, also accompanied by the Middletons.

Birthday Bash

But this holiday has a second purpose: Celebrating a big birthday for proud granny Carole Middleton, who turns 60 Saturday.

Around 30 guests, including the cream of the island’s elite society, will enjoy blues and jazz music in a spectacular villa with its torch-lit grounds.

Among the expected guests: Basil Charles (who owns the landmark Basil’s Bar), Brian Alexander, the former manager of the island’s privately-run company and hedge fund millionaire Dr. Mark Cecil and his wife Katie.

Also part of the babymoon-birthday entourage: Kate’s siblings Pippa, 31, and James, 27.

The Middletons have been visiting Mustique for many years: Carole tells friends of its delights and urges them to go there if they can. She and husband Michael Middleton are so dug-in with Mustique’s wealthy set that Carole invited several residents (including Basil Charles and the Cecils) to be guests at William and Kate’s 2011 royal wedding.

William, Kate and George arrived a little more than a week ago, while her parents joined them a few days later.

“You feel like you are in another world,” says a recent visitor. “It’s like being in paradise.”

Perfect Privacy

For those who treasure their privacy, like William and Kate, it is a perfect place to vacation. There is a no-fly zone over the island. The beaches, while public, can only be seen by non-residents from the sea and the locals know just about everyone who might venture onto the island.

Each villa is secluded, with lush landscaping and expansive grounds that guests safe from prying eyes and traffic. Residents get around in little buggies.

They are believed to be staying at the $21,000 a week Rocina Villa, which comes with a chef, two housekeepers and a gardener. It is where Kate stayed last year when she and George vacationed with her family. William was studying agriculture at Cambridge University at the time.

George The Swimmer

Prince George, who has been learning to swim in the pool at Buckingham Palace, will likely have enjoyed splashing around in the warmer temperatures of the 30-foot infinity pool at the villa.

William, Kate and George are expected back next week. Kate has a royal outing, in Portsmouth, Feb. 12. There, she will visit the home of Britain’s America’s Cup yacht team and see one of her most recent patronages, the 1851 Trust, which supports efforts to get young people sailing.

It is a visit she had to cancel when she was ill with severe pregnancy sickness in her first trimester.

William then throws himself into taking, and hopefully passing, the rest of his exams for the commercial license he needs for his upcoming helicopter pilot’s job with East Anglian Air Ambulance.

It is the last long trip Kate is expected to take before the baby is due in April.