Image copyright The Duchess of Cambridge/PA

Prince George is seen smiling in an England football shirt for official photographs released to mark his sixth birthday.

Kensington Palace published three pictures taken recently by his mother, the Duchess of Cambridge.

The third in line to the throne turns six on Monday.

Two of the images show the prince wearing a white England home shirt and grinning in the garden of his home at Kensington Palace.

A third shows him on a family holiday, wearing a green polo shirt and striped blue and white shorts.

Image copyright The Duchess of Cambridge/PA

Image copyright The Duchess of Cambridge/PA

The Duke and Duchess of Sussex took to Instagram to wish their nephew a happy birthday.

Writing from their official account, the royal couple commented: ''Happy Birthday! Wishing you a very special day and lots of love!"

Image copyright Instagram

The England football team also sent their well-wishes to the young royal, complimenting the prince on his Three Lions t-shirt.

The official account for the England team wrote on Twitter: "Great choice of shirt! Have a brilliant birthday, Prince George!"

Prince George Alexander Louis of Cambridge was born in the private Lindo Wing of St Mary's Hospital in London.

He appeared in front of the world's media one day later, when Prince William and Catherine stood cradling him on the hospital steps.

This year, he has appeared on the Buckingham Palace balcony and at his mother's Chelsea Flower Show garden.

Image copyright PA/Getty Images Image caption By George, how you've changed! Clockwise: Prince George on his six birthdays

Earlier this month, the young prince received a tennis lesson from Roger Federer at the home of Kate's parents in Bucklebury, Berkshire.

The sports star said George was "cute" and had a "good" technique.

Image copyright Reuters Image caption The prince's first appearance, when he was only a day old

A great-grandchild to the Queen, George is expected to take the throne after his grandfather and his father.

The prince has completed Year 1 at the private Thomas's Battersea school.

He will begin Year 2 this September, his final year in the lower school before he moves to the middle school.