The man explained what he'd done and asked Matthew to put his shopping to one side while he went home and got his money. But Matthew had other ideas – paying for the man's groceries himself so he didn't have to make an extra journey.
The store offered to reimburse the money to Matthew, but he declined.
The customer was thrilled with the level of customer service he experienced. He returned to the store later that day to pay him back and also wrote a letter to the store commending Matthew's actions.
Matthew said: "I was more than happy to help! I recognised the hassle it would have caused this man to go home and come back therefore I paid for his shopping. He was quite surprised, however incredibly grateful."
Store manager Dorie Stewart said: "Matthew carried out a fantastic act of kindness, he went the extra mile, and it was a tribute to the whole of our store at Asda West Dundee for the quality our colleagues we employ here.
"He went above and beyond to help a customer and we really appreciate his efforts. Well done Matthew."
Matthew's kindness has been making headlines, with The Scottish Sun calling his story "supermarket sweet". Read their story here.