The Esher's track's 27-28 April fixture will now feature a version of Cheltenham's four major Grade One races - the Gold Cup, Queen Mother Champion Chase, Champion and Stayers' Hurdles - on two, seven-race mixed cards of Flat and jump racing.
The final programmes are expected to be announced within the next 48 hours after discussions between race-planners at the British Horseracing Board (BHB), the sport's treasurers at the Levy Board, Sandown and sponsors of races at the existing Whitbread meeting and the lost Cheltenham Festival.
But Sandown's clerk of the course Andrew Cooper is already describing the enhanced fixture, the last act of the current National Hunt season, as "the most attractive two days of racing this country has ever seen".
Existing crowd-pullers include the Whitbread Gold Cup itself, the 10-furlong Thresher Classic Trial and the Group Three Gordon Richards Stakes.
"The aim is to make both days of the fixture as attractive as each other. They will both have Flat, hurdle and chase contests. The jump racing promises to be of unprecedented quality for a fixture at this time of the season."
