Betfair, the internet betting exchange, has agreed a new five-year deal to sponsor the King George VI and Queen Elizabeth Stakes at Ascot.

Under the deal, the three-day meeting will be rebranded as 'Betfair Weekend'.

The track's most valuable steeplechase will now become the Betfair Ascot Chase, and is likely to form part of the Betfair Million bonus scheme from the 2010 season.

The new deal will raise the value of the race to a minimum of US$1.5 million for the first time. This follows two seasons in which the Royal racecourse has run its premier event without a sponsor.

Stephen Burn, Betfair's director of horse racing, said: "We are delighted to have the opportunity to work with Ascot on this ground-breaking agreement, especially as it will take us up to and beyond the course's historic tercentenary in 2011."

The deal makes Betfair the second largest sponsor in horse racing behind Tote.