The pair share favouritism at 9/2 with the Paul Nicholls’ trained pair of former winners, Denman and Kauto Star, next in at 6/1.
And the bookies reckon a gamble on either of the Nicholls’ greats could result in another twist at the top of the extraordinary betting market.
David WIlliams of Ladbrokes said: “If the punters decide that either Kauto Star and Denman have got a grand hurrah in them, they’ll be backed off the boards.
“Imperial Commander has looked rock solid at the top of the betting for ages but all of a sudden it’s got a whole lot more interesting.”
The Cheltenham Gold Cup is estimated to be worth a staggering £40 million to the betting industry – a race second only to the Grand National in terms of betting interest.