Chris Johnson, a former running back with the Tennessee Titans, New York Jets and Arizona Cardinals, has revealed he has been diagnosed with Motor Neurone Disease/Amyotrophic Lateral Sclerosis.
The 40-year-old, a former NFL offensive player of the year who last played in 2017, said on ABC's that he had been diagnosed with the disease last year.
"We hoped it was something else, but after thorough testing, they finally came down with a diagnosis of ALS," said Johnson in an interview with Michael Strahan in which he had to use a voice modulator because the disease has already taken away his ability to speak.
ALS - the most common type of Motor Neurone Disease and the term most often used in the USA along with Lou Gehrig's disease - is a nervous system disease that affects nerve cells that control muscles throughout the body.
The disease leads to muscle weakness and other symptoms that get progressively worse.
Johnson said he was sharing his diagnosis because if it helps "even one person" get diagnosed sooner or gives another family hope "then it's worth it".
"It's continued to progress much faster than I ever imagined," Johnson said.
"I want people to understand just how quickly ALS can attack your body.
"Just over a year ago, I was picking up my seven-year-old daughter so she'd make a wish with her birthday cake. Today, I couldn't do that."
Johnson added: "I want people to know that I'm still me. ALS has changed what my body can do, but it hasn't changed who I am.
"People sometimes look at the physical disability and assume you're not still the same person inside. I still think the same. I still dream. I still love my family. My body just doesn't cooperate."
Johnson said in the interview that he was diagnosed with the illness last year, aged 39.
He added that there was no history of the disease in his family, adding: "My doctors believe my case is what's called sporadic ALS, which is actually how the vast majority of ALS cases happen.
"That is one of the reasons why this disease can be so shocking. It can happen to someone who never expected it."
Johnson, who was born in Orlando, Florida, attended East Carolina University. He was later snapped up by the Tennessee Titans in the 2008 AFL draft as a first-round, 24th overall pick.
The three-time Pro Bowler led the league for rushing yards (2,006) the following season - earning him the nickname CJ2K - and would go on to make a whopping 9,651 yards across his career, scoring 55 touchdowns in the process.
After spending five years at the Titans, he joined up with the New York Jets for a season in 2014 before moving to the Arizona Cardinals the following year. Johnson would make 130 NFL appearances during his career, starting in 111 of those games.
Johnson would first retire from the NFL after 10 years in the game in November 2018, before signing a one-day contract to retire as a Tennessee Titan in April 2019.
