It's time to take Kevin Federline seriously.

No, seriously.

Mr. Britney Spears, pop culture's favorite punch line, is trying to make money the old-fashioned way — by, um, actually working. The wannabe rapper has a single, "Lose Control." Could this mark a 180 for the man whose most recent "job," reportedly, was getting paid $20,000 to do cameo appearances at clubs and parties?

In the world of celebrities, K-Fed's become the ultimate dead-weight spouse. What's his purpose? His life's goal? His hygiene regimen? We realize love is blind and that no one knows the ins and outs of any relationship except the two involved. (But c'mon, Brit, wake up and smell the sweat-stained trucker cap.)

Sadly, she's not the only famous face to cannonball into the pool of fools. Here's a look at some celebs who, for better or worse, vowed to love some of the biggest hangers-on in entertainment history — and whether the relationship has any chance of being rehabbed.

DEAD WEIGHT: PETER COOK

Weight lifter: Cover Girl supermodel Christie Brinkley

Waste-of-space credentials: The 47-year-old Hamptons architect, who wed the luminous "Uptown Girl" in 1996, thus vaulting himself from relative anonymity onto the pages of People, recently admitted to carrying on a yearlong affair with his assistant, whom he met in a toy store when she was 17. Of course, he only 'fessed up after the now-19-year-old threatened to slap him with a sexual-harassment suit. Days later, a second woman came forward and claimed Cook seduced her when she was 18.

Yes, you are sorry: Cook offered up his mea culpa to the New York Post saying, "I'm sorry. I'm contrite. I'm stupid. Foolish. No excuse." Don't forget liar, adulterer and disgusting pig.

Turnaround potential: Admitting guilt and apologizing was a good first step. Cook said he hopes for a reconciliation, but should it end in divorce, "She can have whatever she wants." Well, she should.

DEAD WEIGHT: KEVIN FEDERLINE

Weight lifter: Britney Spears

Waste-of-space credentials: Well, let's see: He dumped his pregnant girlfriend to run off with Britney. For their wedding celebration, he and his groomsmen donned "Pimp" sweat suits. He revealed to GQ magazine he once earned his living through "criminal mischief."

Yes, you are sorry: K-Fed, 28, firmly denies mooching money from his wife. "As a man, as a male figure and a father, I wouldn't be happy sitting back and living off my wife's fortune." Could've fooled us.

Turnaround potential: Whether he's sporting a fedora or cornrows, Britney seems to love this guy. The two reportedly will renew their wedding vows in a small ceremony sometime after the birth of their second child (his fourth), due this fall.

DEAD WEIGHT: HEATHER MILLS MCCARTNEY

Weight lifter: Paul McCartney

Waste-of-space credentials: We realize Heather does a lot for animal rights, ridding the world of land mines and supporting those, like herself, who have lost limbs. However, for many Paul devotees, something about her (namely that she wasn't Linda) never set well. So it was music to the ears of many when news broke in May that the couple were separating after four years of marriage. British tabloids have reported that Mills McCartney's past allegedly includes photos in a porn book and work as a prostitute. Lawyers believe McCartney could lose up to a fourth of his estimated $1.5 billion fortune because he didn't have Heather sign on the dotted line.

Yes, you are sorry: In response to the British tabloid reports that she appeared in a "hard-core porn book," Mills McCartney admits that's her in the photos but defends the work as a "lover's guide to a caring relationship."

Turnaround potential: She should focus on animals and land mines, because her marriage seems like one lost cause.