Louis is shown sitting on his bike in the grounds of Kensington Palace, smiling for mother Kate – who took the picture on Wednesday.
Wearing a jumper, shirt, shorts and with his rucksack on his back, the prince grips the handlebars and appears ready to cycle off to nearby Willcocks Nursery School – but was taken by car.
Louis celebrates his third birthday on Friday and is following in the footsteps of big sister Princess Charlotte, aged five, who also attended the same nursery.
His birthday is likely to be celebrated with a cake shared with his new classmates – something revealed in the testimonials on the nursery’s website.
The Duchess of Cambridge is an accomplished amateur photographer, who in 2017 accepted a lifetime honorary membership of the Royal Photographic Society which recognised her “talent and enthusiasm”.
End of two-week period of royal mourning
The two-week period of royal mourning following the death of the Duke of Edinburgh ends today allowing the Cambridges to release the image.
The young prince was featured in a picture released in tribute to his great-grandfather, showing Philip and the Queen surrounded by their great grandchildren at Balmoral – with the monarch holding Louis.
The Duchess regularly releases images of her children to mark important occasions like birthdays and other major milestones.
The Cambridges’ youngest child is fifth in line to the throne and was born on St George’s Day, April 23, 2018, at the private Lindo Wing of St Mary’s Hospital in Paddington, London, weighing 8lb 7oz.
He was christened Louis Arthur Charles at 11 weeks old, by the Archbishop of Canterbury Justin Welby at the Chapel Royal, St James’s Palace in front of friends and family.
The young prince has rarely been seen in public – his most prominent outing during the past 12 months was when he joined his parents and siblings at a special pantomime performance at London’s Palladium Theatre last winter.