The Duke and Duchess of Cambridge have used their son's first birthday to issue a heartfelt thanks to everyone who has wished their family well during the past year.

Eastern Daily Press: The Duke and Duchess of Cambridge and the Prince during a visit to the Sensational Butterflies exhibition at the Natural History Museum, London. Photo: John Stillwell/PA Wire.The Duke and Duchess of Cambridge and the Prince during a visit to the Sensational Butterflies exhibition at the Natural History Museum, London. Photo: John Stillwell/PA Wire. (Image: Archant)

As two touching photographs of William, Kate and Prince George were released to officially mark the toddler's birthday, the Cambridges paid their own tribute to the public support they have received.

The Duke and Duchess said: 'We would like to take this opportunity on George's first birthday to thank everyone over the last year, wherever we have met them, both at home and overseas, for their warm and generous good wishes to George and our family.'

William, Kate and George were photographed for the official pictures during a visit to the Sensational Butterflies outdoor exhibition at London's Natural History Museum, of which Kate is a patron.

One image shows George, who will celebrate his first birthday tomorrow, fascinated by a blue morpho butterfly, Morpho peleides, from South America, which has landed on the back of his father's right hand.

The toddler prince, who will one day be king, appears about to pick up the delicate insect as he is sat on a bench with his parents.

In the other picture the Duke and Duchess and their son are transfixed by something above their heads and all three stare at the object, possibly a butterfly.

Sir Michael Dixon, director of the Natural History Museum, said: 'It was a real pleasure to host our patron and her family earlier this month. They seemed to enjoy their visit, wandering through the tropical plants as brightly coloured butterflies took flight around them.

'It was delightful to see Prince George's first experience of the Natural History Museum and I look forward to welcoming them again in the future.'

The Cambridges will celebrate their son's first birthday with close family and friends at Kensington Palace and are expected to hold a birthday party.

In the pictures, taken a few weeks ago by Press Association photographer John Stillwell, George is dressed in a pair of dungaree shorts, over a polo-shirt style top and shoes and socks.

The dungarees are from French brand Petit Bateau while mother Kate is wearing a green 1930s-inspired Budding Heart Silk Tea dress by British brand Suzannah, which sells for £475.