The English symphonic metal band confirmed last year that it was indeed working on something with Sheeran, who is reportedly a massive fan.
In a new interview with Knotfest's Sophie K, CoF frontman Dani Filth confirmed that work on the song is underway. Its completion rests mostly in Sheeran's hands at this point, but Dani believes it will get done.
"We still have yet to finish our song with Ed Sheeran," Dani said. "He's done some of it, but then he had a baby, and then he got obviously sidetracked with that and doing whatever Ed does, which is play massive shows around the globe. He's not at our beck and call. But he's gonna finish it, he assures me. Actually, I spoke to him quite recently."
He added that the song will get a release date "when it's finished." But at the moment, no one knows when that will be.
Dani has described Sheeran as "genuinely very nice guy" and suggested that profits from their song would go to charity.
Sheeran has spoken publicly before about his appreciation for heavy metal, naming Cradle of Filth and Slipknot as two of his favorite bands.
In an interview last summer, Sheeran explained that he learned lots of heavy metal riffs on guitar as a child, but "never thought about" writing a metal song. He added, however, that he "would not be opposed" to trying.
Sheeran is far from the only major pop star to reveal himself as a headbanger in recent years. One of his longtime collaborators, Justin Bieber, has been keen to acknowledge his love of Metallica and Ozzy Osbourne in years past.
In 2019, Bieber surprised the metal world by revealing his lifelong fandom of TOOL and genuinely asking his Instagram followers if there was any crossover between them and the Tool Army.