Saturday October 7 7:49 AM ET, Reuters

LINCOLN, N.M. (Reuters) - Actor Richard Farnsworth, nominated this year for an Academy Award for best actor for his role in "The Straight Story,'' shot himself to death at his New Mexico home, police say.

The 80-year-old actor, who won the nomination for his portrayal of Alvin Straight, an elderly man who drove his lawnmower from Iowa to Wisconsin to see his dying brother, had terminal cancer, said Lincoln Sheriff Tom Sullivan.

Sullivan said Friday that Farnsworth was found dead at the residence he shared with his companion, Jule Van Valin.

"The lady who lives with him heard a gunshot a little after five p.m. tonight and she went into the room and saw him,'' Sullivan said. "She called a neighbor, who was one of my former deputies. ... He went over and found Mr. Farnsworth.''

"This was an obvious self-inflicted gunshot,'' Sullivan added.

"I was just in the other room and I heard the shot," she said in a telephone interview from Farnsworth's home. "He was incredible pain today. He was going down hill."

Van Valin said Farnsworth was diagnosed several years ago with terminal cancer, which had left him partially paralyzed. He struggled with the pain while he was working on "The Straight Story," she said.

"He was very ill in that movie, but phenomenally he made it through. He didn't want the world to know he was sick," Van Valin said.

"He couldn't fight it, and cancer got him."

Farnsworth had said the heart of his performance in "The Straight Story," came from his respect for Alvin Straight, the real-life person on whom his portrayal of a 73-year-old man who rode a tractor across the country was based.

"I admired him very much and tried to be as much like his character as I could, talked to two of his boys, who are now truck drivers, and we filmed along his actual route. Every time we stopped somewhere, people would come by and say, 'Heck, I remember when old Alvin came through,' and tell us about it," he told The Associated Press last March.

At 79, Farnsworth was the oldest leading actor to receive an Oscar bid. "Titanic" star Gloria Stuart was the oldest performer ever nominated when she was nominated for supporting actress at 87.

"It feels a lot better because I'm getting up there in age and might not have a chance again," he said in an interview after he was nominated in February

Farnsworth's weathered face and crystal blue eyes earned him roles in some of Hollywood's most popular movies but aside from Straight, he was mostly relegated to supporting roles.

He played the sheriff in "Misery'' in 1990 and had roles in ''The Getaway'' (1994), "Havana'' (1990), "The Natural'' (1984), and "Comes a Horseman'' (1978), for which he received a best-supporting actor Academy Award nomination.

In Canada, he was nominated for that country's best actor award for his role in the 1982 film, "The Gray Fox.''

Farnsworth was born on Sept. 1, 1920 in Los Angeles and began his film career at the age of 16 as a stuntman. For 40 years he doubled for Roy Rogers and other Western stars but gradually began earning roles in his own right.

In 1990, Farnsworth moved out of his home of 40 years in the Hollywood Hills and came to the outskirts of Lincoln, a town of 565 in the foothills of two mountain ranges that is known for Billy the Kid's famous escape.