The 23-year-old has taken the internet by storm with his down-to-earth approach to weight loss and fitness, becoming a millionaire in the process.

But the Banbridge man is keeping his feet on the ground and still lives at home with his parents. “I’m too well looked after to think about moving out,” he joked.

His SCasey Fitness brand went viral after he started posting on social media about “the truth” of weight loss during the Covid-19 lockdown.

His unconventional approach has gained him five million followers across TikTok, Instagram, Facebook and YouTube.

Countless people have benefited from the advice he dishes out, always with a dollop of craic.

Last month he was on a mission to prove that bread doesn’t make you fat by confining himself to eating nothing but sandwiches for 30-days, while aiming to lose between 4-6kg. He managed to lost 4.5 kgs.

He said: “I managed to eat four sandwiches a day and I haven’t eaten the same sandwich twice!

“I’m did it to prove a point – that you can lose weight while eating bread. Weight loss is about calories and not one food type.

“My love for sandwiches only grew stronger by the day. Sandwiches are so diverse; there are so many different combinations. My inbox was full of messages from people suggesting different sandwich fillings, it was good craic.”

His most unusual suggestion was an apple and Mars Bar sandwich that he made into an “unreal” toastie.

He was fascinated to discover from his followers it came via the Presbyterian Church, being a popular snack at Sunday meetings.

Sean is earning more money than he ever dreamed was possible while doing something that “doesn’t feel like work”.

He has released three best-selling recipe books, runs a one-on-one online fitness coaching business, group coaching through the The Sean Casey Academy and a social media growth course called SC Social Circle.

He is also developing a fitness app called Glean which he believes will revolutionise weight loss and health.

Not bad for someone who admitted he went to university “purely to party” and found himself abusing drugs and alcohol.

“I did a business degree at Ulster University but was doing a lot of drinking and partying and drugs,” Sean said.

“It is not a great position to be in. I had no goals and wasn’t doing much good with my life.

“I had a moment when I realised I had to sort myself out. It was September 2019 and I decided to try and focus on myself, then lockdown happened and I couldn’t go out anyway.

“I had always been in shape because of boxing and sport, which all stopped when I was 17.

“I had put on 13kg and had never had bodyfat before. I started reading, and I found there was a lot of misinformation about fat loss.

“I really wanted to do something positive with my life, so I started to do educational videos on YouTube to share the knowledge which had helped me transform my body. I wanted to help other people do the same.

“TikTok was blowing up at the time, and a friend suggested I post videos on there. I thought it was just for dances and children, but I gave it a go and had 100,000 views in a week.

“I realised there was something in this form of short content and became a bit obsessed with why videos like that performed so well.

“I decided to apply it, and before I knew it I had five million people following me.

“It is absolutely crazy that I am now sitting at 23 with four businesses, earning more money than I ever dreamt.”

Having found the key to success on social media, he developed the SC Social Circle to help others follow in his footsteps.

After studying for personal trainer qualifications, he launched The Academy Group coaching platform, which has helped thousands of people.

As he devotes most of his waking hours to his clients, the money is rolling in, but Sean insisted the joy was in making it, not spending it.

He said: “I’m switched on all the time, but it doesn’t feel like work. I’m passionate about what I do and am not materialistic. I don’t want the big house in Dubai and all the trappings (of wealth).

“I never thought I would make this much money, but to me it is a by-product of what I am doing. I love the process of actually earning the money, rather than spending it.

“I have paid my parents’ mortgage off and bought my mum a Tesla, but for me the fun at the minute is in developing my new fitness app.”

As well as his uncomplicated approach to health and fitness, Sean believes keeping it real has helped his businesses.

He said: “People put this polished version of themselves online. That is not being real. When I come on, you get what it says on the tin, I am unapologetically myself. I don’t do brand deals.

“People are not getting lies or a person pretending to be something they are not. I have a monotone voice, and I can’t change it, but people know me and we have fun.

“I hope young people can see there are opportunities to pursue something that doesn’t follow the normal route. You just need a passion. If you can talk about something you are passionate about, you can build a business, but you have to really care about it. If you do, you can change your life.”

Follow Sean on social media @scaseyfitness