The family, likely still getting over jet lag after returning from New Zealand and Australia (Prince George took three days to get over traveling there), is spending the day "privately," a spokesman says, as they relax with their 9-month-old son.
Insiders predict the Duke and Duchess of Cambridge will also share their stories of the heady 19-day tour with Kate's parents, Mike and Carole Middleton. The Middletons were in Scotland at a wedding when William, Kate and George returned Saturday.
The couple have some downtime before parting later this week, when William, 31, jets to Memphis for the wedding of close friend Guy Pelly to Lizzie Wilson. William and brother Prince Harry, 29, are ushers at the ceremony, which is expected to take place at a polo club.
Insiders believe it's likely that Kate, 32, will take her son to spend some time with her parents in Bucklebury, about 50 miles west of London.
Soon, William and Kate will put the finishing touches on their early summer engagements, which will see a "significant upsurge" in public appearances by them and Prince Harry. They will likely head to the Commonwealth Games in July and, in August, may represent Queen Elizabeth at the upcoming commemorations of the beginning of World War I.