After a year that saw both King Charles and Kate Middleton diagnosed with cancer, “Obviously it made sense it had some form of health connection," a source said
The current Princess of Wales — then the Duchess of Cambridge — went the thoughtful, heartfelt route with her gift for her first married Christmas in 2011
“It was the first time the Queen had extended such an invitation,” royal biographer Robert Lacey said of asking a girlfriend to the traditional royal Christmas
In Andrew Morton’s landmark biography of Diana, he writes her disdain for royal family Christmases began as early as 1981, the year she married Prince Charles