No one is truly certain about the big V except the celebrities themselves, making chastity declarations a vague publicity stunt that stars can use to portray themselves as innocent and pure, according to Elayne Rapping, professor of pop culture and media studies at the State University of New York, Buffalo.
"It's a way to differentiate yourself from the mainstream Hollywood image of everybody sleeping with everybody else," she said.
Unlike Spears, fellow blonde bombshell Jessica Simpson ostensibly kept her promise. "The Dukes of Hazzard" star was the poster teen for abstinence during the beginning of her career. Simpson often pledged to save herself for marriage before she and Nick Lachey ever became "Newlyweds" although Lachey admits he didn't do the same.