See More Business, who won the 1999 Cheltenham Gold Cup, has died at the age of 24.
The Paul Nicholls-trained chaser also twice won the King George VI Chase in a superb career.
"He was what jumps racing was all about," said Nicholls. "For me it's been a privilege and an honour to be involved with him."
See More Business won 18 of his 36 starts under rules and retired in 2003 with career earnings of £701,722.