Just two months after Britain's Prince William and Kate Middleton got engaged, an official coin marking the occasion has been unveiled.

The second-in-line to the British throne and his bride-to-be, both 28, are featured on one side of the £5 collector's piece being produced by the Royal Mint.

But royal fans may have trouble recognising the couple, who are to tie the knot in April next year — an image that bares some likeness to Prince William is shown in profile, but Ms. Middleton is face-on and appears older and overweight, The Sun reported.

The coin was designed by the Royal Mint's in-house engraving team and has Queen Elizabeth in profile on the reverse.

The piece is the first royal engagement coin produced by the Royal Mint and was approved by the Queen and Prince William.

A Royal Mint spokesperson said:

“The inspiration for the design came from photographs of the couple at a sporting event — the play on the traditional portrait is that Prince William is seen in profile, alluding to his royal status.”

When asked about Ms. Middleton's likeness, the spokesperson stressed that the design “does go through a rigorous approval process.”

Many commemorative medals and coins have been created by the Royal Mint in honour of the monarchy during its 1,100-year history.

When Prince William's father Prince Charles married Lady Diana Spencer in 1981, the event was marked by a coin showing the couple in profile with the Queen's image on the reverse.

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