At the time of decimalisation in 1971, the United Kingdom Crown coin (equal to 5 shillings) was redenominated as a 25p coin and pieces struck prior to 1990 - all the way back to 1818 - continue to be legal tender for that amount. The old denomination had been a regular circulating coin in the 19th century, but in the 20th century it became more of a commemorative denomination.
The Royal Mint continued issuing commemorative coins in the same format - using the traditional coin dimensions, but in copper-nickel. These were initially also denominated as 25 pence but the "Crown" was changed in 1990 to a commemorative £5 (five pound) coin, having the same dimensions and weight but with a face value twenty times as great.
The denomination is used to mark special occasions, usually royal in theme, rather than for use in general circulation. Although not circulating, these coins are legal tender.
This commemorative £5 Crown-sized coin celebrating British artist George Michael is part of the eighth release in the Music Legends coin series by the Royal Mint.
The mint says:
George Michael went from a teen heartthrob as part of the pop group WHAM! to one of the bestselling solo musicians of all time, selling more than 125 million records. His passing in 2016 devastated millions of his devoted fans around the world. This coins is a tribute in recognition of his remarkable talent as one of the world’s most popular and beloved musicians.
Inspired by George Michael’s iconic music video for "Faith", the design is available in a range of editions that includes a colour-printed Brilliant Uncirculated edition. | 
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