First stamps featuring King's silhouette are a nod to his love of gardening
The silhouette of King Charles will be featured on a collection of 10 stamps celebrating the nation's favourite flowers.
The uncrowned profile of the King, a passionate gardener and environmentalist, is painted in silver and faces the top right corner.
The sweet pea - a favourite of the late Queen - is among the chosen flowers in the collection. Another celebrates the sunflower, which is the national flower of Ukraine.
David Gold, Royal Mail's director of external affairs and policy, said: "Britain is a nation of gardeners, and a love of flowers runs deep in our collective consciousness.
"His Majesty is known to be a passionate gardener and we are delighted that the first special stamps to feature his silhouette should be a celebration of some of the most popular flowers in British gardens."
The creation of the King's silhouette was a collaboration between illustrator Andrew Davidson - known for his illustrations of Ted Hughes's children's book The Iron Man - Marcus James, the Royal Mail's head of design and editorial, and Ian Chilvers, from design agency Atelier Works.
The first-class floral stamps are available for pre-order from today on the Royal Mail website.
Other flowers included in the collection are a purple iris, a pink lily, a fuchsia, an orange-red tulip, a dark pink peony, a bright orange nasturtium, a pale pink rose and a light purple-tinted dahlia.
At his mother's funeral, the King chose flowers cut from the gardens of Buckingham Palace, Clarence House and Highgrove for the gold, pink, deep burgundy and white wreath which rested on her coffin, and included pink garden roses and dark purple dahlias.
A Royal Mail spokesperson said: "Flowers mark our celebrations, our joys and our sorrows and, above all, they unify us through a pleasure that we can all understand."
King's stamp unveiled by Royal Mail - and there's one big difference from the Queen's
The definitive stamps - those just showing a profile image of the monarch - which were unveiled last month and go on sale in April, show Charles without a crown and facing left as all monarchs have done since the Penny Black in 1840.
Unlike the iconic stamps with the silhouette of his late mother, Queen Elizabeth II, the king is not depicted wearing a laurel wreath - a feature on the Queen's profile since 1966.
The final set using the Queen's image was unveiled last month to celebrate the 100th anniversary of the steam locomotive, the Flying Scotsman.