Broadcaster and journalist Charlie Bird says he is "scared" after being diagnosed with motor neurone disease.
The 72-year-old publicly announced his diagnosis on Wednesday morning.
In a tweet, he said: "Recently I spoke about issues with my voice. I now know why.
"I have been diagnosed with Motor Neurone Disease.
"Thanks to all my pals for their amazing support. And the kindness from so many people."
Speech issues are listed among the symptoms of motor neurone disease, a condition that affects the brain and nerves.
Mr Bird spent 38 years across a number of roles in RTÉ, before retiring in 2012.
In September, he said he declined two radio interviews due to having "major issues" with his speech for the previous four months.
But Charlie told The Hard Shoulder he started to notice changes back in March.
"It's going back to probably March of this year.
"On Patrick's Day I was out walking in the mountains, and I started to choke on a sandwich which was unusual.
"And then it all started to tumble out then... I was doing an interview with the famous four gold Willie McGee in May for a podcast series, and my voice really started to weaken.
"And I knew I needed medical help at that stage."
Charlie says he got the full diagnosis last week.
"I've been waiting for the past four months to find out what the hell was going on and unfortunately last week, we got the diagnosis of motor neurone.
"I was going through a whole series of tests and to be honest they were coming back not showing anything.
"Sometimes, apparently, motor neurone is very difficult to diagnose - and I think in my case it was".
He says his walking abilities are unaffected at the moment, and he is taking full advantage.
"I've been walking up to 10 miles and sometimes more every day.
"My mobility is not affected at the moment, but as you can hear my voice is seriously damaged - and will probably get worse in the weeks and months ahead".
'Other people have had hard knocks'
And he says while it is hard to take, everyone has hard knocks in life.
"This is all a hard thing to take in, and as I said earlier today - and I'll repeat it - there have been other people in this country who've had hard knocks even harder than mine, and my heart goes out to them.
"Among them is Vicky Phelan, who to me is a hero of mine - what she has gone through and how she has dealt with herself.
"We all get knocks in this life, and mine is a really difficult one to take, but that's it - you have to deal with it.
"You can't turn and hide from it - so in a way... during the summer, I was hiding from it.
"I was hiding from my neighbours, I was hiding from my former RTÉ workmates, I didn't want them to know.
"And then eventually a few weeks ago I tweeted I was having issues, and I felt that was the time to come clean and be honest".
He adds that he would be lying if he says he wasn't scared.
"Yes I'm scared and I'll be blunt - over the last period I've cried sometimes.
"But everybody goes through difficult periods.
"It hasn't been easy, but the one positive thing is that I've had amazing support...from my team mates, colleagues, people I've worked with going back for nearly 40 years.
"They gave carried me - if people only knew what they have done for me, psychologically and emotionally, they would be proud of them as I am of them."
But he says losing his voice is tough, as it is what he is known for.
"In a way for me, my voice is the thing that was my flag, people knew me because of my voice and my face for being on television.
"It's been tough but... my mates in RTÉ have been amazing.
"My family - I've two daughters, Orla and Nessa, son-in-law, five grandkids, and my beautiful wife.
"I'm lucky, I'm so lucky".