The grime artist was even knifed in the head.
Stormzy, 25, who grew up in Croydon, south London, told others about his past while on a course, aged 17.
He said: “It was in Tipton. In the room were 17 white kids. One day we had our hard hats off. I had a scar on my head, and someone goes: ‘What happened?’
“I said: ‘Oh, I got stabbed.’ I will never forget.
“I was explaining: ‘I got stabbed here, there, there.’ They had faces of horror – and that’s when it dawned on me.”
“I was explaining: ‘I got stabbed here, there, there.’ They had faces of horror – and that’s when it dawned on me. Of course it’s shocking I’ve been stabbed. Of course it shouldn’t be normal.”
The artist – real name Michael Omari – is passionate about boosting opportunities for black youngsters.
He said seeing black role models in successful jobs helps raise aspirations, adding: “Acting’s had a lot to do with that – John Boyega, Daniel Kaluuya, Letitia Wright – that spark is powerful beyond measure, as to what it does for the community.”