Jon Arnold only planned to run the first leg of this year's Belfast Marathon when he signed up for the relay event.
He rocked up to the starting line wearing a pair of rugby shorts, a charity shop t-shirt and a pair of trainers that "cost me a tenner", while his training had consisted of two 6km runs.
But the 37-year-old from County Down went on to prove that you should never judge a book by its cover, reports Belfast Live.
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Not only did Jon complete his designated 4.1-mile leg from Stormont Estate to Montgomery Road, but he went on to complete the other four legs of the relay to finish the full marathon distance of 26.2 miles in five hours 20 minutes.
Now he hopes his story can motivate anyone out there who may be considering a marathon.
Jon - from Castlewellan - said: "I didn't go out with the target of finishing the full marathon. I just went out to finish my relay leg, and then things progressed from there.
"Once I completed my leg I thought I would try and complete the next one, and before I knew it I was at 21 miles and on the final leg.
"A friend who was with me asked 'are you going to stop now?', but I had to keep going at that stage. It was probably when I was running up Ormeau Road and along the home stretch, that's when I thought 'I can do this'.
"I knew once I hit the top of the Ormeau Road that it was all downhill from there. So once I got past that I knew I could do it.
"I just wanted to push myself and see how far I could go. If someone had asked me beforehand if I could run a marathon, I would have laughed at them.
"But once I broke it down into small milestones, that made it a bit easier completing the full thing."
The longest run Jon did before last weekend's marathon was "about nine years ago" when he completed the last two legs of the relay.
"I haven't ran the length of myself since then," he laughed.
"I was getting mocked and teased by my family. I am a Type One diabetic, so they were more concerned about my health and wellbeing.
"They didn't think I could achieve the four miles of the relay, let along 26.2. I hadn't dedicated my life to training or anything like that.
"I did two 6km runs as preparation. Most of my training was running around after my two kids, and that was it."
To make Jon's achievement even more remarkable is the fact he ran the full marathon wearing an old pair of trainers he originally bought to play indoor football.
"I literally found them lying in the back of my wardrobe. I have had them for about 10 years," he joked.
"I think they cost me a tenner and I bought them to play indoor football. I just threw them on and I didn't have any problems with them.
"I didn't have any injuries or blisters afterwards, while my friend who had proper running shoes had blistered feet.
"But I don't think I will be getting any sponsorship off Nike or whatever. I was literally a no-frills runner.
"I wore rugby shorts even though I don't play rugby. My top was from a charity shop and cost me about £3."
Jon kept his family members updated as he journeyed around Belfast, but none of them believed he was still running as the day progressed.
"My wife's mum called me halfway through asking where I was. I told her I was still running and she replied, 'what do you mean you're still running?'.
"I think she thought I was still running my leg of the relay. I told her I was in Andersonstown and she didn't believe me.
"When I got to Ravenhill Road, close to the finish, she was the first person I rang. I asked her to guess where I was and she replied, 'are you in hospital?'.
"I told her I was almost at the finish line and she couldn't believe it.
"I also finished the marathon with two of my best mates which was special, and quite hilarious. One of them was running the final straight and being sick at the same time.
"The crowd was cheering at one stage and then gasping the next."
Jon admits crossing the finishing line was an emotional experience.
"It was. It was a special moment, and it only hit me then what I had achieved," he said.
"I didn't look at the time, but it was very overwhelming. I called my wife and she didn't believe I had completed the full marathon distance.
"I don't have the motivation to go out running long distances. Family life usually takes over so I don't have time to go out on long runs.
"I admire people who can fit it in. Fair play to them.
"This was very much outside of my comfort zone, but you never know what you can achieve. I just wanted to challenge myself and see what I could do."
Having got a taste of the full marathon experience, Jon says he might take on a few more challenges in the months ahead.
"My friend has mentioned the Dublin Marathon to me, which is in October. I laughed at him," Jon said.
"But now, after completing a marathon, I have realised my fitness levels and potential. My time wasn't competitive, I openly admit that.
"But my goal wasn't about getting a personal best or a medal, it was just challenging myself to see if I could complete 26.2 miles.
"I am now contemplating Dublin, and I have signed up for the Belfast Half Marathon. I tried signing up for next year's London Marathon but missed out on the deadline for the ballot.
"But I am sure there will be something down the line."
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