At the time, Bosley was suffering from lung cancer. "We talked about his strength and that it was coming back," Winkler, 64, who played Arthur "The Fonz" Fonzarelli on Happy Days, tells PEOPLE.
"He had just gone through several bouts of chemo, and you always heard him in a positive, forward attitude. He was always looking forward, you know. At 83, I hope that's me."
Bosley, who died Tuesday at his home in Palm Springs at age 83, is set to be buried in a private funeral in Los Angeles on Friday.
"He had that wonderful, sprite-like energy of his," Winkler says. "It was apparent on the phone when I spoke to him three weeks ago, it was apparent when we saw each other a year ago, it was apparent when we saw each other before that."
Bosley, says Winkler, resembled his character Howard Cunningham on the '70s sitcom they costarred in. "He was feisty and funny," he says, "and the relationship between he and Marion [Ross] on and off the screen, they were just great. It was always, 'Oh, Tommm.' It was just great."
Winkler also points out the late actor was a positive role model on the set and through the last days of his life, and was always there to offer fatherly advice to the cast.
"When you are going into buying a house and you needed to get insurance and stuff like that, he would break it down, he would explain it," Winkler says, "and then he would tell you who you had to talk to and find a good an insurance person and so on and so forth and you knew at least what the right questions were to ask."
One of Bosley's last projects was the Jennifer Lopez film The Back-Up Plan, released this year.
"I think one of the most important things for a human being no matter what your industry is a sense of relevance, that you stay active and that you are working towards something," Winkler says. "And it was very important for Tom. Whoever worked with him was very lucky because he brought an enormous amount of experience and an enormous amount of wonderful talents. He was one of our best character actors."