Guess "Duke" and "Duchess" are little formal when you're on the couch watching X Factor.
Although just-married Prince William and Kate technically have a new surname -- Cambridge -- the happy couple have private names for one another at home in Anglesey.
"For day-to-day life, they are the Cambridges," a source tells Us Weekly of the Duke and Duchess of Cambridge, 28 and 29. "But behind closed doors they are calling each other Mr and Mrs Wales. It's cute."
And William also takes that more-casual approach on the job as a search and rescue pilot at the Royal Air Force base in Anglesey, where he and his new wife continue to live post-wedding.
"He will still be known as Flight Lieutenant William Wales," St. James' Palace confirms to Us.
Indeed, a guest at the couple's Friday wedding lunchtime reception (hosted by Queen Elizabeth) at Buckingham Palace tells Us that the Prince toasted his new wife similarly, declaring, "I'd like to raise a toast to Mrs. Wales."
Says the guest: "To call her Mrs. Wales [instead of 'Duchess'] I thought was very touching...in England you often announce your surname, and it's a very proud thing when your wife takes your surname...they'll be a very low-key couple. They want to be very down to earth."