Two years ago, the Pussycat Dolls were a risqué L.A. burlesque troupe whose eye-popping live shows drew a celeb-heavy cult following and guest dancers like Carmen Electra and Christina Applegate. This week, they're radio faves with a slinky top 10 hit called ''Don't Cha.'' That a barely dressed vamp act became a charting pop group with a major-label album (due Sept. 13) is strange enough. What's more curious is that the very same tune was a minor radio hit earlier this year. The original was sung by Atlanta-based makeup artist, stylist, and former OutKast backup singer Tori Alamaze. Unfortunately for Alamaze, her version only reached No. 53 on Billboard's Hot R&B/Hip-Hop Songs chart and Universal dropped the singer before her full-length CD came out. The label then asked the song's producer and writer, Atlanta rapper/singer Cee-Lo, to rerecord ''Don't Cha'' with the Pussycat Dolls, who it was trying to reinvent as a slick girl group. ''Initially, I was skeptical, I didn't know too much about them,'' says Cee-Lo. ''But when I found out that [Universal-owned] Interscope Records was involved, that was an alliance I didn't hesitate to make.'' The two records are strikingly similar (save for a guest rap from Busta Rhymes on the Dolls'). Admits the group's lead singer Nicole Scherzinger: ''I had [Alamaze's] version as a guide. But ours is just a bit fresher.'' Not surprisingly, Alamaze is irked: ''I like to call them the Copycat Dolls. It's an attempt to sound like what I did, but it just sounds real watered-down.''