The coins feature a double portrait for only the fifth time

It is only the fifth time in history that a double portrait has appeared on a British coin.

The other side of the coin was inspired by the stained glass rose window at Westminster Abbey, where they married.

It has also been announced that the Queen and Prince Philip will attend the US's prestigious Kentucky Derby horse race on 5 May.

'Easily recognisable'

The coins, issued by the Royal Mint, commemorate the 60th anniversary of the couple's wedding on 20 November 1947.

The last time a double portrait appeared on a coin was for their golden wedding in 1997.

Engraver Emma Noble said she became focused on the rose window while sketching features of the abbey.

The reverse was inspired by Westminster Abbey's rose window

"For me, it was the one element that really stood out and was easily recognisable," she said.

"I am thrilled that my design has been chosen to commemorate such an important occasion in British royal history."

The coin is inscribed with "My strength and stay", the words used by the Queen to refer to Prince Philip on their golden anniversary.

The Queen and the Duke will go to the Kentucky Derby following a two-day visit to Virginia.

They will commemorate the 400th anniversary of Jamestown, the first permanent British settlement in the present day US.

They will then meet President Bush and his wife Laura in Washington.