The coin will feature a garland of roses embossed onto its side, and its design has been approved by the Queen herself.
The mint is offering the coin for free to pensioners who turn 90 on the same day of as the Queen on April 21.

The coin comes in a variety of metals including silver, gold and platinum gold, and prices vary from £20 to £5,000 for a rare platinum edition.
Artist and sculptor Christopher Hobbs, who designed the coin, told the Mail on Sunday: “I wanted it to be a simple design which had the feel of continuity – after all, the Queen has reigned for 63 years.”