For the last two weeks, 16-year-old Tiffany has ruled the singles charts with "I Think We're Alone Now," a remake of an old Tommy James & the Shondells song that was a hit before she was even born.

This week, the California teen slipped all the way to No. 4, but the chart champ is still a Shondells remake. That's because Billy Idol's new version of "Mony, Mony" had just enough momentum left to slip into the top spot ahead of the Bill Medley-Jennifer Warnes duet "The Time of My Life" (up from No. 3 to No. 2), which is already No. 1 in radio airplay and on the adult contemporary chart.

"Mony, Mony" is the first No. 1 in the U.S. for Idol (his real name is William Broad), a former star of the British punk scene who finally has broken through with an all-out, mainstream hit.