The 73-year-old actor and artist attended the Breeders' Cup in support of The V Foundation for Cancer Research, the official charity of the year-ending thoroughbred championships Saturday at Santa Anita Park in Southern California.
It was revealed last month that Hopper had been diagnosed with cancer, although he said Saturday he's been battling it for the past nine years. He's started a new, experimental treatment at the University of Southern California that he says he hopes will help.
"It has great promise," Hopper said. "Everything's good right now."
Hopper recently canceled his appearance atan exhibition of his artwork and photography at the Australian Centre for the Moving Image in Melbourne. He was hospitalized in New York last month and treated for dehydration.
Hopper is one of racing's biggest and best-known fans. He's been to five Breeders' Cups, including last year when he said he cashed a $17,000 trifecta ticket in the Classic, the signature race on thoroughbred racing's championship day.
He's disappointed horse racing has lost some of its luster among the public but he believes the sport carries its own style and swagger that is alluring.
"It would be a drag to see the industry come down," Hopper said. "It's such a great tradition. I hope it gets well and goes on forever."
Hopper wouldn't say who he was going to choose in the Classic, only to note that Zenyatta, a 5-year-old mare, is a formidable foe for her male rivals.
"You can't count her out," he said.
The "Easy Rider" star recently finished shooting the second season of "Crash," a TV version of the Oscar-winning 2004 film. Hopper also has several film projects in the works.
Related Content from AccessHollywood.com:
VIEW THE PHOTOS: Hollywood Legends