Bill Ritter started “forgetting people’s names and places” two years before his Alzheimer’s diagnosis.

The ABC New York anchor “didn’t know why this was happening,” so he stepped away from the channel’s 11 p.m. and 5 p.m. newscasts, he told “Good Morning America” viewers Monday.

While only doing the 6 p.m. show allowed the 76-year-old to get “a decent night sleep … for the first time in 25 years,” his symptoms weren’t “getting better.”

It was then that Ritter knew he had to “get tested.”

He recalled, “That really was an important thing. A lot of people say, ‘I’m fine, don’t worry about it, I’m going to be fine.’ No. You gotta go do this.”

Ritter, who went public with his diagnosis on Friday while announcing his retirement, said his “first reaction” to the results was his dad “popp[ing] into [his] head.”

Ritter’s father, notably, died of the same disease in 1998.

“Then a couple of seconds later, I was scared,” Ritter remembered. “I don’t mind saying that. It was scary. Because it was like, ‘Wait a minute, I’m supposed to be doing this. What’s going on here?’

“I quickly moved into husband/dad place,” the journalist continued. “Because Alzheimer’s really affects the family most. As a dad and a husband, I said, ‘I gotta deal with this. This is my family. And that’s what I’m really worried about.'”

He called his loved ones “the brave ones” in the tragic situation.

When Ritter shared his diagnosis on Friday, he said, “Spending more time with my family has now become even more important, because my life has taken a turn.”

He added, “The treatments I’m getting are keeping it at bay. For now. But there is no guarantee, because there’s no cure yet for Alzheimer’s. So, unless someone finds an amazing cure, and soon, tonight will be the last newscast I anchor.”

Ritter, who has been at WABC since June 1998, is “going to so miss reporting the news.”

He will, however, will continue working with “Eyewitness News” to help cover Alzheimer’s disease — a special “opportunity” he addressed on “GMA” Monday.

“After this interview, I’m going to go to our Monday morning meeting at 9 a.m. … and then I’m going to go to my desk and have day one of the new job,” Ritter said. “And that will be to bring people into the tent, because I think that’s what we want.”