Last August, the winningest coach in college basketball history stunned the sports world with a sad announcement: University of Tennessee women’s basketball legend Pat Summitt revealed that she had been diagnosed with early-onset Alzheimer’s disease.

In an exclusive interview airing Friday on ABC News’ “ 20/20,” Summitt told Robin Roberts that she has no regrets about going public with her disease.

“Initially I was like, you know, ‘How am I gonna do this?” she said. “I just said, ‘Gotta do it.’”

She drew a lesson, she said, from the late President Ronald Reagan, who also struggled with Alzheimer’s.

“I was working out, and … they had the Ronald Reagan story on. And I was sitting there, looking at it, and they were telling his story. And, you know, first he did not come clean as to what [he] really had,” she said. “So I sat there and watched it that day, and I remember I had tears coming down my eyes, and I said, ‘Well, that could be me.’”

The Reagan connection didn’t end there: Former first lady Nancy Reagan sent Summitt a letter of support.

“She said, you know, I heard about your diagnosis of dementia, and I just wanted to reach out to you and just tell you, you know, that it’s going to be OK,” Summitt said.

Summitt said she wrote back to Reagan, thanking her.

“It just meant the world to me that she reached out,” she said. “I just got the chills.”

 Watch the full story on “20/20? Friday at 10 p.m. ET.