Jamie Harrington from Ballymun told the page's curator, 27-year-old photographer Peter Varga, that he had seen a young man sitting on a bridge when he was walking through the city.
"I saw this guy in his 30s sitting on the ledge of the bridge. I just thought, 'wow'," Jamie says.
"I stopped and asked him if he was okay, but I knew from the look in his eyes he wasn't, and he didn't say anything either, but I saw tears coming from his eyes."
Jamie stayed and spoke with the man, and ensured he was brought to a hospital to be cared for.
"I pleaded with him for a while to come down and sit on the steps, and eventually he did," Jamie says.
"We sat on the sidewalk on the south side of the Liffey and talked for about 45 minutes, about what was happening to him, why was he feeling that way.
"I couldn't leave him there alone, but I had to go, so I was going to ring an ambulance. I told him they could help him feel better. But he was like 'please, please don't call them, I'm fine, I just want to walk around for a while, I'm gonna be okay!'
"I told him to please let me ring an ambulance, that I wouldn't sleep knowing he was just walking around alone. So I rang it, and he was taken to St. James Hospital."
The man and Jamie have since remained in touch, and he is thanking Jamie in a very heartwarming way.
"I got his number so I would know what was going on with him for a good while," Jamie says.
"And about three months ago, he texted me that his wife is pregnant, they're having a boy, and they're naming him after me. Can you believe that? They're going to name their child after me.
"He said in that moment that I approached him, he was just about to jump, and those few words saved his life. That they're still ringing in his head every day. "Are you okay?"
"I can't really understand how these few words could save his life, but he told me, 'Imagine if nobody ever asked you those words.'"
Jamie's story has touched the hearts of the public, and his photo has been liked over 20k times.
Jamie has previously spoken out about mental health in Ireland, having been diagnosed with depression when he was 13, and is an ambassador for organisations such as SpunOut.ie and Teenline Ireland.