The Queen has reportedly not invited Kate Middleton's family to the traditional Christmas lunch, which she organises every year at her Sandringham Estate in Norfolk.

According to Daily Mail, the Duchess of Cambridge, Prince William and baby Prince George have been invited to the event, but Kate's parents, Carole and Michael Middleton, sister Pippa and brother James have not been included in the guest list.

"It is highly unlikely that Kate's family will be invited to the big Christmas lunch, or the famous Boxing Day shoot. Perhaps one day they will be invited to the big house for tea, but not for lunch or dinner, and not on Christmas Day," a royal source said.

"The Queen is fond of Kate and doesn't mean to exclude her family – indeed she has broken many of the old rules for them in the past.

"But if all of her children and grandchildren's wives had their families to lunch, there wouldn't be enough room, even at Sandringham House's dining room," 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, 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.

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