The Duke and Duchess of Cambridge celebrate their fourth wedding anniversary on Wednesday – as they await the birth of their second child.
With the baby overdue, the couple are spending time at Kensington Palace, as they wait for Kate to go into labour.
Unless Kate is admitted to hospital, it’s expected the couple will mark their anniversary privately in a low key manner.
The royal baby could make an appearance on the royal wedding anniversary
The Duchess was spotted driving herself away from Buckingham Palace yesterday.
The heavily-pregnant 33-year-old was said to have been taking son George to use the pool at the Queen's London residence.
Swimming is one of the best forms of exercise for pregnant women, with the water supporting their bump.
The Cambridges, who met at university, married at Westminster Abbey on April 29 2011, watched by a global television audience of millions.
Fourth wedding anniversaries are traditionally marked with gifts of fruit or flowers, but royal fans are hoping the baby will make it a double celebration for the Duke and Duchess by making its debut before the end of the day.
Fewer than one in 20 women give birth on their due date. On the NHS, induction is offered to women who go two weeks overdue, but Kate is having her baby at the private Lindo Wing of St Mary's Hospital, in Paddington, London.
April 29 is also the 50th birthday of Kate's uncle Gary Goldsmith - the brother of her mother Carole Middleton.
Actor Sir Daniel Day-Lewis, former cricketer Phil Tufnell, actress Michelle Pfeiffer and Edward VII's mistress Alice Keppel - the Duchess of Cornwall's great-grandmother - were also born on April 29.
The funeral service of the Duchess of Windsor, for whom Edward VIII abdicated the throne, took place at St George's Chapel on April 29 in 1986.
William and Kate's wedding anniversary is now the favourite date for the arrival of their new son or daughter, with bookmakers William Hill giving odds of 7/2.
But punters are also betting heavily on a big baby, with a child weighing between 8lbs and 9lbs the new favourite, cut from 9/4 to 6/2.
Rupert Adams, of William Hill, said: "Punters are latching on to the fact that the baby is increasingly late and believe that, as a result, Kate will deliver a whopper."
Betfair suspended betting on the royal baby being born on William and Kate's anniversary after a string of bets.
Coral said Alice remained the favourite name at 5/4, but that Victoria was proving particularly popular - with odds being cut from 12/1 to 7/1. William and Kate do not know whether they are having a boy or a girl.
Royal super-fans, who have been camped outside the Lindo wing for more than a week, were treated to a special delivery of pastries from the Cambridges on Tuesday.
William and Kate thanked ardent supporters at St Mary's Hospital in Paddington, London, by sending them two boxes of breakfast pastries and coffee.
Well-wishers believe the royal baby - who will be fourth in line to the throne, the Queen's fifth great-grandchild and a younger brother or sister for George - could be a girl after the parcels arrived wrapped in pink ribbon.