London, April 26 (IANS) A gambler has placed a bet on Kate Middleton wearing the Queen's over 90-year-old diamond tiara at her wedding with Prince William, a media report said Tuesday.

If the gambler's hunch is right, The Sun said that it would mean Kate has borrowed the Queen's priceless tiara.

Wearing it would make Kate Friday the first "commoner" to use it for her wedding.

The tiara was made in 1919 for Queen Mary and it is formally known as the George III Tiara.

A middle-aged woman tried to lay the 6,000 pounds wager at Ladbrokes in Ascot, Berks.

She was turned away as the manager was convinced she had inside information.

The woman then travelled to nearby Egham, where she obtained odds of 12-1, the media report said.

In case she is right, she stands to gain 72,000 pounds - making it the largest stake on the wedding so far.

Till now, Kate was tipped to wear flowers.

Betting firm Ladbrokes has closed the book on this bet.

"If the punt comes home, we'll lose a fortune. This woman either has more money than sense, or she is very well informed," spokesperson Alex Donohue was quoted as saying.