Kate Middleton and Prince William are reportedly planning to spend Christmas day alone.

According to Grazia Magazine, the Duchess of Cambridge and Prince William will join the Queen at at her Sandringham Estate in the morning, but later will leave for their Anmer Hall residence in Norfolk.

The 32-year-old royal, who is pregnant with her second child, has been suffering from hyperemesis gravidarum, a potentially serious pregnancy illness causing vomiting and a bodily reaction to the intake of food and liquids.

"William spoke to the Queen about doing their own thing, especially since Kate has been suffering with acute morning sickness. He thought it would be nice for her to have a low-key Christmas. The Queen agreed," a source told the publication.

"Kate, William and George will join the royal family on Christmas morning before parting ways until Boxing Day. They will rejoin on Boxing Day for the annual shoot," the insider added.

In a break from royal tradition, in 2012, William and Kate had spent Christmas day with the Middletons at their Bucklebury home in Berkshire.

Meanwhile, Kate and the Duke of Cambridge are to make their first visit to the Big Apple during a three-day tour of the United States next month.

The royal couple will travel to New York for a series of official engagements between 7-9 December.

It was recently reported that the second royal baby is due next April.