Ladbrokes are to sponsor the former Hennessy Gold Cup as part of a five-year deal covering 13 races on the two days of Newbury's biggest jumps meeting.
The Hennessy has been a fabric of National Hunt racing from its inception in 1957 and began life at Cheltenham until it was moved to its present home in 1960.
It has been won by such stars of the winter game as Mill House, Arkle, Bregawn, Burrough Hill Lad and Denman.
With the original sponsors ending its backing, Ladbrokes have stepped in and will increase the value of the big race by 25 per cent to £250,000.
The Ladbrokes-sponsored meeting will take place on December 1-2 this year, with total prize-money over the two days increasing by almost £100,000 to £700,000.
Ladbrokes are not an Authorised Betting Partner, but Newbury said a deal with the bookmakers had been reached as the existing Levy scheme will be replaced by the Government in April.
Newbury chairman Dominic Burke said: " Given the Government's position, our board felt that it could agree future sponsorship arrangements with any betting operator for race meetings taking place after that April date."
Jim Mullen, chief executive of Ladbrokes Coral Group, added: "We have committed to work in partnership with Newbury Racecourse to build the two days of this fixture into one of the most compelling attractions not just in the racing calendar, but in that of sport as a whole."
The only race Ladbrokes will not sponsor at the two-day fixture is the Sir Peter O'Sullevan Handicap Chase on the Saturday, which will continue to be supported by the friends of the late BBC racing commentator, journalist and fundraiser.