Brett Favre says Parkinson's diagnosis came in January after problems with his right arm

Brett Favre told TMZ Sports He was diagnosed with Parkinson's disease in early January after first experiencing problems using his right arm and hand.

The Hall of Fame quarterback made the revelations to us in late August while discussing various football topics. At the time, he asked us not to report on them, but after made his diagnosis public during a hearing on Capitol Hill on Tuesday – he gave us permission to publish it.

Favre said he first suspected something was wrong when his dominant arm – with which he had thrown 508 touchdown passes in his 20-year NFL career – “got stuck.”

He said he would push it down and forget about it…but seconds later, “it would be back.”

He also admitted that although he had no strength problems, he could not easily hold the screwdriver with one hand when he wanted to use it.

However, he said he ultimately went to the doctor because he was having trouble getting his throwing arm through a hole in his jacket.

“I felt my arm,” he said. “I had the strength, but I couldn't control it. That was the most frustrating thing ever.”

Favre says after he was officially diagnosed with the degenerative nervous system disorder, five specialists told him they believed it was likely due to the blows he took while signaling in the NFL.

“They all said the same thing,” he said. “'If it doesn't run in your family' – and there's no paternal or minor in my family – 'then the first thing we look at is head injuries.' Well, damn it, I wrote the book on head injuries.”

Favre, who once said he may have suffered over 1,000 concussions over the course of his career, seemed optimistic about his prognosis … and told us one of his doctors said most people are already much more scarred by the disease by the time they learn about it.

On Tuesday evening, hours after the world learned of his illness, he posted a statement on his social media page thanking all those who were praying for him.