Lewis Capaldi says he realised he had made it big after he was allowed to use the staff toilet in Sainsbury’s.
The star was caught short during a day out with friends in Glasgow.
He dashed into a branch of the supermarket chain only to be told they had no toilets for customers.
However, a star-struck shop assistant recognised the Someone You Loved singer and let him to use the staff loos.
Asked when he first realised he was famous, the 23-year-old, from Whitburn, West Lothian, said: “I was in Glasgow and I was walking down the street going from one bar to another bar and I really had to pee.
“I had had a few beers and I was like, ‘Oh God, I’m going to pee myself here’. I jumped into a Sainsbury’s and I said, ‘Look, I’m really sorry, do you have a bathroom I could use?’
“The guy said, ‘I’m sorry, we don’t have a bathroom in here’. Then he went, ‘Are you Lewis Capaldi?’
“It was one of the first times that happened and I was like, ‘Yes, I am Lewis Capaldi and I need a pee’.
“Then he said, ‘Well we’re not supposed to do this but you can use the staff toilet in the back’.”
Speaking to US radio station Hot 103.9, Lewis added: “For me that was the day when it all came together and I thought, ‘I’ve made it here’.
“It was not when I went and met Elton John, not when I played Glastonbury, not when I went to No1 in America. It was the day I was allowed to pee in a staff toilet.
“Now when I go into places and I ask to use the toilet and they don’t offer the staff toilet, I feel quite offended and think, ‘I might not be doing so well here, I’ll need to put out a new song’.”
