Britain's Prince William will join Duchess Catherine and her family on their Caribbean holiday.

While the Middleton family jetted off to the island of St. Lucia on Wednesday (18.01.12) without the 29-year-old royal, it is understood he will join the group - which also includes Catherine's sister Pippa and brother James - after he finishes his weekly shift as an RAF search and rescue pilot in Anglesey, North Wales.

The sun-soaked holiday could be the last chance the couple get to spend some quality time together before William is deployed to the Falkland Islands for a six-week period with the RAF next month, the Daily Mail reports.

It is believed that since flying to St. Lucia on a scheduled British Airways flight, the family transferred to the private island of Mustique, where they are regular visitors at a multi-million pound cliff-top villa - which comes complete with five bedrooms and its own infinity pool.

Catherine is incredibly close to her parents and has previously revealed her hopes that she and second-in-line to the throne William will be as close to their own children.

She said: "It's very important to me. And I hope we will be able to have a happy family ourselves. They've been great over the years - helping me with difficult times. They are very, very dear to me."

William has also spoken about how "lucky" he felt to have been welcomed by Catherine's parents during the course of their relationship.

He explained: "Catherine's got a very, very close family. I get on really well with them and I'm very lucky that they've been so supportive. Mike and Carole have been really loving and caring and really fun and have been really welcoming towards me, so I've felt really a part of the family."