For better or worse, T-Pain popularized auto-tune.

But he didn't invent the technology, so nobody had to pay him for its use.

According to Diddy’s engineer Matt Testa, Puff Daddy did anyway.

"At that time, T-Pain was heavy on the Auto-Tune and was running up the charts,” he said, speaking on  Diddy-Dirty Money’s Last Train to Paris album. “Puff played it off as a joke, but was serious when he told T-Pain, ‘I want your permission to use auto-tune.’ T-Pain was like, ‘Yeah, whatever. It’s not mine, you can use it.’ He ended up giving Pain a royalty point on the album and [the agreement] was written on a napkin. Pain definitely got that point because I spoke to him recently."

T-Pain, who has had pretty serious money problems lately, has expressed bitterness about how the auto-tune era played out.

“It was just a whole generation of people like, if you get T-Pain on this you can do exactly what he does. And then after that, you don’t have to get him anymore because he’s already solidified, he’s got the T-Pain stamp and he can just keep running with it. I got tricked into other people stealing my swag," he told The Breakfast Club in 2017.