The mural created by Austrian artist LUSHSUX features an image of Spade making a peace sign alongside the Neil Young lyric "It's better to burn out than fade away," which Cobain quoted in his 1994 suicide note.
A confused Spade confirmed it was his face alongside the quote after multiple fans alerted him of the mural.
"Picture that was on mural. Why it's on it who knows," Spade said. "Oh well. I blame that crazy internet."
Several fans pointed out the image originated as an internet meme from 2016 in which photos of celebrities were matched with misattributed quotes.