If Brittany Murphy’s voice could be photographed, I’d advocate putting it on the sides of milk cartons; that’s because — like Elvis, Tupac, and Britney Spears’ sex appeal — it’s quite possibly alive and well and strutting under our noses in total anonymity. Indeed, the actress — whose collaboration with Paul Oakenfold, “Faster Kill Pussycat,” is up to No. 8 on this week’s Billboard’s Dance Singles Sales charttells Cosmopolitan (scroll down) that she has anonymously lent her vocals to “a lot of other people’s albums,” and hears herself on the radio “all the time.”

Which, of course, has me obsessing: Where have we heard Murphy belting before? Bush frontman (and Gwen Stefani husband) Gavin Rossdale appeared in Murphy’s 2004 romantic comedy, Little Black Book, while her breakout picture, 1999’s Girl, Interrupted, featured another erstwhile singer, the non-gay Jared Leto, but those dudes seem unlikely collaborators for a dancefloor diva like Murphy. I’ve got a better theory: Murphy hosted SNL on Nov. 16, 2002, with a musical guest by the name of Nelly. Do you think that maybe, just maybe, it could be Murphy cooing the famous “Hot in Herre” lines, ”I am/Gettin’ so hot/I wanna take my clothes off”? Until one of you guys chimes in with a more plausible sighting hearing, I’m choosing to believe it, since, like her character in Don’t Say a Word, she’ll (probably) never te-el.

addCredit(“Brittany Murphy: Jeffrey Mayer/”)