When he decided to leave secondary school his teachers asked him what he intended to do with himself. "I told them I wanted to be a football player and they all laughed. It's good when people don't believe in you and you prove them wrong."
Watt is 18 now and still in single figures in terms of appearances for Celtic. He's also about the most unassuming and humble player on the club's books, which means he'd be the last to claim he has made it as a footballer. Others can be bold on his behalf. As a strong, mobile forward with a finisher's instincts he scored two on his Celtic debut as a substitute last season, two more on his first start last weekend, and he's played in an Old Firm game and a Champions League qualifier. That's not bad going given that yesterday was the first anniversary of the day he scored against Barcelona in a NextGen series match.
Amusingly he has made a bit of a name for himself as a rotten trainer at the club's Lennoxtown base. Manager Neil Lennon mentioned it in an interview last week and he has said so to the teenager directly. Other players have teased him, too. "Everyone who's seen me says I'm not a good trainer, but if I can do it in games then obviously I'll be happy. Sometimes when I'm in training and I do something wrong it sticks in my head and starts playing on my mind. But on the park you can't afford to do that you. Training and games are different. In front of 60,000 fans you don't have time to lack confidence.
"The manager said in an interview that if something doesn't work for me in training my head will go down and my body language is wrong. Maybe he means that . . . or maybe he just means I'm hopeless in training. I haven't been getting pelters from anyone in training, they help you through and have a laugh and slaughter you, but it's not meaningful, it's just to wind you up and have a laugh. Everyone does it."
The ribbing is gentle because whatever he fails to do on the training field he makes up for in games. If he can seem a quiet, reserved figure around training, it is not reflected in his single-minded ambition to make it in football.
When he left school he went to the gym every day and got some mundane nine-to-five work. "It was an office job with North Lanarkshire Council just to get myself out the house. It was an apprenticeship and there was nothing for me to do. I sat at my desk every day, bored. If I was still there I'd probably be sitting on my backside now doing nothing. But I was sacked for going down to Liverpool on trial. I had a phone call the day I was sacked. I told them I had to go to the trial and they told me to choose one or the other, so I said, 'see you later then.' I had to make a choice and football obviously came first."
His father, Paul, believed in his boy's talent to the extent he supported the loss of the office work. "My dad was 100% behind me. He said if that was what I wanted to do then go for it. The schoolteachers all asked me, 'what are you leaving school for?' If I was ever talking to kids like that I would tell them to go for their dreams and try to achieve them. I spoke to my dad and I spoke to my old manager recently and I said, 'two years ago would you have expected all of this for me?' And to be fair they both said 'aye'. I thought 'no'! But even my agent has told me since I was first playing that they believed I could go all the way."
He has been a Celtic player since an £80,000 move from Airdrie United in January. At times he has not found it easy to come to terms with the quality of player around him, yesterday naming Gary Hooper, Scott Brown and Victor Wanyama as among the most impressive. "You are in awe of players like that but they're my team-mates now so I just have to get on with it. You want to impress your team-mates. I just don't get ahead of myself. It's not about putting myself down, but being self-critical helps me become a better player. If I'm bad at something I'll try to work to improve at it. I won't say I'm brilliant at something when I'm not."
Watt rubbed shoulders with more established Celtic players on Thursday when they gathered at Lennoxtown to watch the Champions League group draw. The demands of that tournament may create openings for him in the SPL, if Lennon believes he has to husband his resources and rest the likes of Hooper, Georgios Samaras or any other striker for league duty. Having scored twice at Inverness last weekend and impressed in a cameo as a substitute against Helsingborgs, it would be a little harsh on him if he did not feature against Hibernian at Parkhead today. And if he plays, Hibs should be worried about him being harsh on them.