Henderson has high hopes for Long Run, despite a poor run in March
Long Run will attempt to dethrone four-time winner Kauto Star in the King George VI Chase on 26 December.
Trainer Nicky Henderson revealed the Kempton plan for the five-year-old at his annual owners' day.
Cheltenham's Paddy Power Gold Cup in November is the first target for Long Run, who has grown an inch since coming third in his last race in March.
He finished more than seven lengths adrift of Weapon's Amnesty in the RSA Chase at the Cheltenham Festival.
However, that disappointing run no longer worries Henderson, who said: "I've an inkling Long Run was over the top by Cheltenham.
"He'd had a busy time of it, having been on the go in France since the previous spring, and I believe that had caught up with him. He did not look quite right in his coat.
"After a break immediately after the festival he came back looking marvellous. Having grown an inch he has developed into a big, strong gelding.
"Long Run was stunning when winning the Feltham over the King George course and distance last Christmas.
"I'm sure that sort of three miles is going to suit him best, though there's every chance he will stay further - don't forget he's only a young horse."
Kauto Star, the Paul Nicholls-trained 10-year-old, who last year became the first horse to win the King George in four consecutive years, is due to defend his crown on Boxing Day.
Second only to the Cheltenham Gold Cup among the most prestigious chase prizes, the King George has never been won by any horse on five occasions.
Desert Orchid also won the King George four times but not in four consecutive years.