A chance meeting in a bar led Robert Plant to his latest musical collaboration, an unlikely team-up with celebrated tenor Alfie Boe, a star of British musical theater.

Boe is best known for his turn as Jean Valjean in 'Les Miserables,' but he's also a huge classic-rock buff. He'd always dreamed of working with the former Led Zeppelin frontman, and once they got to chatting and discovered they're fans of each other's work, they made plans to hit the studio. The result is a cover of Tim Buckley's 'Song to the Siren,' a '60s classic Plant recorded for his 2002 solo album 'Dreamland.'

Speaking with the UK's Sunday Mercury, Plant said that the Boe duet, like his recent Grammy-winning collaboration with bluegrass great Alison Krauss, allowed him to showcase his ever-improving musicianship.

"The evolution of my voice is like playing a guitar," Plant told the paper. "The more you play guitar, the more dexterous you become, the more your fingers move faster and all that sort of thing."

The song is due to appear on Boe's forthcoming 'Alfie' album, which arrives Oct. 31, and a rep for Decca Records says the pair might get together for some live shows.

"Having been called the Bad Boy of Opera it is entirely fitting that Alfie should welcome Robert Plant onto his new record and, somewhat surprisingly, their voices blend beautifully," the rep said.

Watch the Video for Robert Plant's 'Angel Dance'