Grand Armee, the two-time Queen Elizabeth Stakes winner who spoiled Lonhro's farewell to racing, has died aged 18.

The former Tulloch Lodge warrior died overnight in his stable at Tim Boland's Limitless Lodge on the NSW Central Coast, where he spent his post-racing career.

Also a Doncaster Mile winner, Grand Armee was a dominant force in Sydney in the early 2000s, claiming seven Group One races and delivering trainer Gai Waterhouse and owner Alan Bell more than $5 million in prize money.

Grand Armee won 13 of 31 starts and finished runner-up 10 times, including to Makybe Diva in the 2005 BMW Tancred Stakes.

Danny Beasley is in no doubt about Grand Armee's place among the turf's modern-day heroes, having ridden him to most of his greatest wins, including the thrashing of Lonhro in 2004 Queen Elizabeth Stakes.

"Best horse I ever rode," the former jockey posted on Twitter.

"He was a bloody good horse and he had such a great character

"I really loved that horse, RIP big fella."

Waterhouse said she was saddened to hear the news.

"A horse I hold dear to my heart & provided me with so many career highlights," she said.

Grand Armee's character was also noticed at Limitless Lodge, which said he was loved by all at the farm.

The gelding reached international CIC 1-star level in eventing before he showed the way for younger horses during his retirement.

"He was a great mentor for the babies, especially holding their hand on the water walker," Limitless Lodge said.

"He will be buried next to Limitless and remembered forever as the great champion he was."