EXCLUSIVE: Britney's Mystery Man

TMZ has learned exclusively that the mystery man who has been at Britney Spears' side isn't a "manny," isn't single, and might actually know less about raising kids than Britney herself.

Britney's hitherto mysterious companion is Perry Taylor, a 28-year-old Naval Academy graduate who played on Navy's lacrosse team and who grew up and went to high school in the Washington, D.C., area.

What's more, quelling rumors that Perry may be taking the place of K-Fed, Perry's mom, Caroline, tells TMZ her son is living with a six-foot brunette (she's Perry's height) and that she's been his girlfriend for two years. Perry's mom calls the girlfriend "a bombshell" and coos she's "the best girl he's ever been with. They're really happy."

Perry and his paramour moved to the West Coast so that Perry could pursue a career in private security. The All-American kid, who graduated from the Academy in 2000, wanted to work in security in Iraq and Afghanistan but, says his mom, "the women in his life talked him out of it." He got his current gig working for a security company, and, according to his mother, worked for another blonde celeb, whom she wouldn't name. Mom says she had never even heard of Britney Spears until her son started working for her.

And if there was any question about whether he was helping out with the Sean Preston diaper detail, his mother told TMZ that the answer's pretty clear: "He's just beginning to learn about babies," she says, adding that not too long ago he asked a friend of his how old babies have to be before they open their eyes.