It happened 14 years ago in Toronto, when Kanter – a producer and songwriter who works with artists like Justin Bieber, Carly Rae Jepsen and Ariana Grande – was a university student and a young musician.
Although they didn't have tickets, Kanter and two friends camped out at Massey Hall one night, hoping to see the legendary blues musician.
The trio's persistence paid off – not long after they caught a glimpse of him heading inside the venue, King's tour manager approached and offered them free tickets near the front of the stage.
It was an amazing concert, he said, but the night didn't end there.
After the show, Kanter and his friends waited by the stage door with some other fans.
Time passed. The crowds dwindled.
And then, when only the three of them remained, King's tour manager re-appeared and offered to bring them backstage to meet the "King of Blues."
In King's dressing room, the musician was friendly, signing autographs for Kanter and his friends and sharing his massive fruit tray with them.
Backstage at Massey Hall
"We chatted about guitars and music. It was my first time ever backstage… at Massey Hall," said Kanter.
"Massey is my favourite venue in the whole world, so it was really special at the time."
Over the years, that night has stayed with Kanter.
As he rose to prominence himself, playing guitar and acting as a musical director for Justin Bieber, he's made sure to do the same for other fans – offering up free tickets and face-time with Bieber.
To Kanter, it just makes sense to show them the same kindness and consideration B.B King once showed him.
"I always think of me waiting outside Massey Hall and how much that experience influenced my life."