Designed by artist John Bergdhal, the coin is the first collectable UK 50p to celebrate a royal event.
The coin will depict the Queen on horseback and will be minted on the 'heads' side of a new 50p and traditional £5 crown, to mark her 70 years on the throne.
The Royal Mint said the design has been personally approved by the Queen and is reminiscent of the equestrian designs for the 1953 Coronation and 2002 Jubilee crown pieces.
What has been said?
Clare Maclennan, the Royal Mint’s Divisional Director of Commemorative Coin, said: “The Platinum Jubilee is an historic occasion and one that is particularly special for The Royal Mint, as the original maker of British Coins for 1,100 years.
“In celebration of this landmark event, the official Platinum Jubilee collection, including the new 50p and traditional £5 crown, features a unique commemorative design on both sides of the coin.
“Designed by esteemed artists and made with original craftsmanship, Her Majesty’s Platinum Jubilee coins are enduring pieces of art that will be collected, cherished and passed down for generations.”
Chris Barker, Royal Mint Museum Historian, added: “The Queen’s legacy on coins stretches the length of her momentous reign, with The Royal Mint striking five definitive portraits of Her Majesty on official UK coin and celebrating previous Jubilees.
“The 1977 Silver Jubilee crown was the first major UK commemorative coin produced at The Royal Mint’s Llantrisant home, after the minting in London ceased in 1975. Roughly thirty-seven million coins were produced at that time, and thousands were gifted to children across the UK as a memento of the occasion. Today’s launch marks another significant milestone, and The Royal Mint plays a proud part in the nationwide celebrations.”