Denman, who won the 2008 Gold Cup and was one of the best-known names in National Hunt racing, has been retired.
The 11-year-old, whose rivalry with Kauto Star has dominated the sport in recent years, suffered an injury during his preparations for the Lexus Chase later this month at Leopardstown.
Trainer Paul Nicholls said: "It is with great regret that I have to announce the retirement of Denman.
"A scan revealed tiny damage to his near fore tendon."
Nicholls added: "Denman was great on Wednesday morning as he worked towards his intended start in the Lexus later this month, but he pulled up a little bit sore yesterday morning and [head lad] Clifford [Baker] wasn't happy with him.
"So we called [vet] Buffy [Shirley-Beavan] in to scan him and that revealed the problem with his near fore tendon.
"We immediately informed his owner Paul Barber who, after consulting those close to him, took the decision to retire him.
"It was the only course of action to take."
Welsh jockey Sam Thomas rode Denham to his 2008 Cheltenham highlight while the Nicholls-trained star also landed the 2007 Lexus and the Hennessy Gold Cup in both 2007 and 2009.
He initially enjoyed success in novice hurdles but only really marked himself as a real star when he switched to fences and defeated his rivals by 10 lengths and more in the Royal & SunAlliance Chase at the 2007 Cheltenham Festival.
Denman followed that up later that year with an easy win under top weight in the Hennessy at Newbury before going on to claim the Lexus Chase.
A Cheltenham Gold Cup showdown with stablemate and reigning champion Kauto Star soon followed and Denman galloped to glory by seven lengths under Sam Thomas.
He was heavily backed to repeat that triumph the following year, but Kauto Star got his revenge.
Nicholls's charge turned in a truly memorable weight-carrying performance to win a second Hennessy in 2009, competing off a 13lb higher mark than in 2007 and giving nearly a stone and more to each of his rivals.
That was to be Denman's final victory, although he chased home Imperial Commander in the 2010 Gold Cup and filled the same position behind Long Run last March.
He was last seen when finishing a lacklustre fifth in the Bowl at Aintree in April and while he will no longer be in training, he will be stabled with Nicholls until the end of this season.
"He will be given an honourable retirement," said Nicholls. "But for the immediate future and to help his great friend Kauto Star, he will be kept in his box next to Kauto for the rest of season.
"Denman will always be a legend here at Ditcheat."