During a clip from the upcoming Netflix documentary This Is Pop, T-Pain recalls Usher, who he considered to be his friend, having him woken up on a flight in 2013 to have a conversation.

T-Pain stated, “Usher was my friend. I really respect Usher. And he said, ‘I’m gonna tell you something, man. You kinda f***ed up music.'” T-Pain explained that he thought Usher might’ve been joking, but Usher repeated his claim, telling him, “‘Yeah man you really f***ed up music for real singers.’ I was like, ‘What did I do? I came out and I used Auto-Tune.’ He was like, ‘Yeah, you f***ed it up.’ I’m like, ‘But I used it, I didn’t tell everybody else to start using it.'”

While Jay-Z slammed the popularization of auto-tune on The Blueprint 3’s “DOA,” T-Pain said that Usher’s stinging comment was the start of a 4-year depression for him. This Is Pop launches on Netflix today.