To follow up his smash single "No Lie," featuring Drake, 2 Chainz delivered another high-profile collaboration with "Birthday Song," alongside Kanye West. And though the reception was tepid initially, it added another element to the Atlanta rapper's buzz and surely helped contribute to his Based on a T.R.U. Story debuting at No. 1 on the Billboard 200 this week. In a recent interview with Fuse, Tity Boi explained how the song came to life.

While on his tour bus, Chainz played Yeezy a song that he was working on. "We probably listened to the song for about an hour; just looped it," he recalled. "And he was just freestyling. I'm like, 'Why don't he go in the damn booth?'"

Luckily, though, Kanye didn't go in the booth, and it gave Chainz the chance to play another record: the Sonny Digital-produced "Birthday Song." "He like, 'Whoa! I wanna do that,'" the long-haired rapper remembers. "And I'm like, 'You do?' It's kinda like, got a trap feel to it. And he was like, 'I wanna do this.' And then we recorded and it took a—when 'Ye record, that's not it. That's just not it. He recorded and I thought that was it."

It wasn't, though. They saw each other a little while later in New York, and Kanye asked his partner in rhyme to send him the files to the song. "I was like, 'Oh, Lord,'" 2 Chainz continued. "We went in and out on the third verse. We combined—what we tried to do was combine worlds. He was trying to show me the stadium side, he was trying to get me to think outside of the box. He thinks of the person that's in the middle of Summer Jam. And I think of the little dread head dudes at my show that's been drinking too much and swearing everything. And we just combined the stadium with both."