Sweet-voiced pop singer Ed Sheeran, in one of the stranger recent musical juxtapositions, covered Iron Maiden's "Run to the Hills" on the Tonight Show With Jimmy Fallon.

The occasion was a fake infomercial for an album called Ed Sheeran Sings Heavy Metal. Fallon said this imaginary product would find "America's cherub-faced pop music troubadour" reinterpreting some of "the darkest, most skull-crushing songs ever written."

As you can see in the above clip, Sheeran plays it pretty straight, offering the song as a lilting acoustic number before inevitably cracking an ironic smile during Bruce Dickinson's familiar chorus. An appropriately scary background image featuring storm-swept graveyards is superimposed behind him.

"Run for the Hills," the lead single off 1982's The Number of the Beast, was Iron Maiden's first-ever Top 10 U.K. hit. Their most recent studio release came with 2010's The Final Frontier. A planned follow-up has been delayed by Dickinson's health issues; he's recently been declared cancer-free.

Meanwhile, perhaps the earliest recording of Iron Maiden recently surfaced online. Taped in 1977, the 29-second clip features second frontman Dennis Willcock introducing the band. Willcock followed co-founder Paul Day and was replaced by Paul Di'Anno in 1978. Dickinson took over in 1981, just before the band found breakout success with The Number of the Beast, Iron Maiden's initial U.S. platinum release.

See Iron Maiden and Other Rockers in the Top 100 Albums of the '80s

Rock and Roll Hall of Fame's Worst Snubs

More From Classic Rock 105.1