Smashing Pumpkins frontman Billy Corgan has passionately rebuffed the public misconception that Nirvana icon Kurt Cobain was a slacker.

While Speaking to Metallica‘s Lars Ulrich on his It’s Electric radio show on Beats 1, Corgan got heated when discussion turned to Cobain’s work ethic while making Nirvana songs, he said the idea that Cobain “would roll out of bed, take some drugs and write a fucking classic” was absurd.

“Kurt Cobain as a lyricist, as a songwriter, as visionary was a fucking assassin. He was great at what he did and it’s a shame he didn’t do more of it,” Corgan argued.

“He let people believe that he was the guy that was [like], ‘Uh, yeah, you know, uh…’”

“How many nights do you think, that long before Nirvana he sat in a fucking basement, trying to figure out, ‘Why does this chord go with this chord?’”.

“And listening to Nirvana’s early demos, listening to Nirvana’s first album, listening to the second album – his voice is changing. It’s not just changing physically, he’s finding the character of Kurt Cobain.”