Kate and William holidaying in the Caribbean

Kate Middleton, 31, was hospitalised in December last year for Hyperemesis Gravidarum, an acute morning sickness characterised by intractable nausea, vomiting, and dehydration.

She is now staying at a 19,000 pounds-a-week villa on the island of Mustique. The luxury pad boasts an infinity pool, games room and stunning views of the Caribbean Sea, 'The Sun' reported.

The royal couple also have Kate's parents Michael and Carole staying nearby.

"The Duke and Duchess have joined the Middletons for a winter break," a source said.

"Both William and Kate were hoping her condition would not stop her from making the eight-hour flight to Barbados and the connection to Mustique," the source added.

"A month ago such a journey would have been unthinkable for her, so this is a clear sign she has made a virtual recovery," the source was quoted by the paper as saying.

Kate and William have enjoyed more than six holidays on Mustique since they started dating.