For the picture the Duchess of Cambridge sported a light-coloured jumper and wore her trademark brunette locks in loose curls around her shoulders. Dressed like his father, who sported a light blue shirt, adorable George wore a dusky blue jumper bearing his name over a white shirt.
The image of the royal trio was taken through an open window at the couple's London residence Kensington Palace and was captured by Jason Bell, who was the official photographer for George's christening in October.
Prince William aged nine months in New Zealand
The photo is significantly being released as Kate approaches her first Mother's Day as a mum. Over the past week the 32-year-old Duchess has been telling friends that she is "very excited" about Sunday's national day and the family's first overseas tour.
Mothering Sunday for Kate will no doubt be spent quietly either in Kensington Palace or at the Middleton's family home in Berkshire so the Duchess of Cambridge can congratulate her own mother Carole.
Britain's future Queen, Princess Elizabeth aged eight months
The new photo of William, Kate, George and Lupo was taken mid-March, after the youngster returned from his first holiday abroad. Kate and George joined the Middleton family on their annual trip to the Caribbean island, while Prince William remained in the UK due to his agricultural studies at Cambridge University.
Following on from the experience of his first long-haul flight, young George will soon accompany his parents on their three-week tour of New Zealand and Australia where royal fans expect he will make a couple of public appearances.