We've seen Ken Hirai do it time and time again: mesmerize audiences with his silky tenor voice and those sexily svelte good looks -- kneading the air up on stage as if to squeeze from it any drop of passion that his music has somehow failed to discharge.

Thirty years old and 183 cm of lanky seduction, Hirai sets hearts aflame with sensuous performances of funk- and R&B-inspired numbers with titles like "Strawberry Sex," "Love or Lust" and "Ladynapper."

It comes as some surprise, then, that for the past month, the Osaka-born performer has topped the Japanese singles charts not with another steamy love ballad, but with a 19th-century American tune called "Grandfather's Clock," known until now mainly as a grammar-school song and lullaby for cranky newborns.