There was a flurry of wagers the royal baby would arrive on what is William and Kate's fourth wedding anniversary.
She is believed to be about a week overdue - as was with her first child, George, and the couple are biding their time at Kensington Palace before the Duchess goes into labour.
Unless Kate is admitted to hospital, the couple will mark their fourth anniversary privately in a low key way at their London home ahead of a busy few weeks with a newborn to care for.
Kate was spotted driving herself away from Buckingham Palace yesterday.
The couple, who met at university, married at Westminster Abbey on April 29, 2011, watched by a global television audience of millions.