"Pretty Woman," "Clueless," "The Devil Wears Prada"...Hollywood loves a good makeover story. Perhaps that explains why so many celebrities dramatically change their looks (usually with the help of an A-list Beverly Hills plastic surgeon), until one day you open up Us Weekly and think, "Who the heck are these people?" Whether they're gearing up for a stay in the Witness Protection Program or just want a fresh start, these 15 celebs barely resemble their younger selves. (And no, Michael Jackson didn't make the cut (no pun intended)-we choose to believe he was abducted by aliens and replaced by a creepy imposter sometime in the mid-'80s.)

When she stole our hearts as ladder-climbing Joey Potter on "Dawson's Creek," Katie Holmes was all about the swinging dark brown ponytail, the shy smile, and the large, innocent eyes. Then she met Tom Cruise, had a baby, upgraded her wardrobe, and chopped off her pretty locks in favor of a hairdo that can only be described as "Short & Sassy Soccer Mom." Katie, you're in your 20s, not your 40s. It's okay to wear makeup and brush your hair!

According to CelebrityCosmeticSurgery.blogspot.com, Katie's hair isn't the only thing to have been on the chopping block. Dr. Anthony Youn notes that her nose is much slimmer now, most likely the result of rhinoplasty. Says Youn, "Personally, I like the older nose better, but the newer one makes her look more mature and older."

Older, yes. Prettier, no.

It's the same old story: Girl appears in cult '80s films, becomes engaged to Johnny Depp, and gives big-nosed girls the world over hope that one day Patrick Swayze will pull them out of the corner too. Then Girl gets a nose job, loses her signature look, and is never seen or heard from again. Welcome to the world of Jennifer Grey.

"I went in the operating theatre a celebrity - and come out anonymous," the "Dirty Dancing" star told StarPulse.com. "It was like being in a witness protection program or being invisible. I remember going to a restaurant where I had been going for years. I ran into people I knew and would say, 'Hey.' Nothing. I'll always be this once-famous actress nobody recognizes... because of a nose job."

The lesson: If a facial feature helps you stand out, don't touch it - no matter how deviated your septum may be.

Not since "The Wizard of Oz" has someone's face melted onscreen at the same rate as Mickey Rourke's. This former heartthrob was the bad-boy sex symbol of the '80s before returning to the boxing ring from 1992 to 1996, which reduced his face to a pulp. Bad plastic surgery has only made the problem worse, and now his face looks like it was carved out of wax.

Writes TheAge.com.au, "Rourke can barely move his own face any more anyway. Of course, all those punches in the gym scrambled his features, but then a lot of shoddy plastic surgery plumped up the scramble and set it into position. He seems to have been something of a surgery junkie, in fact, having his lips inflated and his forehead ironed out endlessly until he was halfway to becoming the Bride of Wildenstein. The sly, seductive smirk doesn't work any more; those boyishly appled cheeks have been rearranged and there is something dangerously Joan Crawford about the flare of the eyebrows. 'I went to a certain kind of doctor,' he says morosely. 'I believed it would make things different.'"

Well, it is different. Just not good.

If Mickey Rourke is the male poster child for 1980s stars who have had extreme plastic surgery makeovers, Melanie Griffith is his female counterpart. In a transformation that makes the big-haired-Staten-Island-secretary-to-Wall-Street-power-player metamorphosis she made in "Working Girl" look like child's play, Griffith has gone from a vivacious, fresh-faced bubbly blonde to a woman with a plastic, expressionless face.

Writes The Daily Mail, "Her skin was taut across the forehead and cheekbones, while her full lips appeared to have the makings of the notorious 'trout pout.'"

Melanie's husband, Antonio Banderas, has reportedly banned her from further surgeries, but if we had to guess she's already had collagen lip injections, Botox, an eye lift, and a breast lift - at least.

When Nicole Richie first appeared on our radar screens as Paris Hilton's sidekick on "The Simple Life," she had ultra-long hair and a little baby fat. By contrast, Nicole 2.0 has a blonde bob and a little baby fat (literally) but still probably weighs less than 100 pounds.

So how did Nicole make the transformation from a fun-loving, healthy-looking girl to a skeletal, blonde fashion android? Several theories abound. CrabbiesHollywood.com points to breast implants; People.com says that Nicole has squashed rumors of a gastric bypass; and Hollywood.com quotes her as saying that she wants a nose job.

"If I could change anything about myself it would be my nose--I hate it," Nicole says. "I'd get a nose done like Kirsty Hume's; she has my kind of nose but smaller. I see really good nose jobs in L.A. but it's a big decision."

Sigh. We miss the old Nicole.

If you were to compare Billy Bob Thornton in "Sling Blade" to the Billy Bob Thornton of today, you'd think that they were maaaaybe cousins-but definitely not the same guy. Has Angelina's ex gone Hollywood on us?

According to AwfulPlasticSurgery.com, the answer is yes. "Billy Bob Thornton no longer looks like a middle-aged guy striding towards his senior citizen years," the site says. "He now looks like a middle-aged guy with really tightly stretched skin. ... 'Subtle' is not how you'd describe his plastic surgery."

In fact, since he split with Angelina Jolie, Billy Bob's look has gone from grizzled roadie to plastic-faced car salesman.

You know what this means...she and Brad Pitt can never break up.

If you look up "reinvention" in the dictionary, a photo of Madonna will pop up. She's been blonde, brunette, muscular, curvaceous, Kabbalist, Catholic, a cowgirl, a disco queen, a geisha, a material girl...we could go on and on. "Who's That Girl?" isn't just a song-it's a way of life.

But has Madonna's evolution involved more than some hair dye and a cone-shaped bra? According to ContactMusic.com, she's had a little surgical help. Says surgeon Apostolos Gaitanis, "I suspect she has been enhanced by cosmetic surgery. Her jawline looks less soft and better defined. This may have been done with a mini-lift which involves the tightening of over-relaxed facial muscles and the removal of excess skin."

Throw in some Botox and a good personal trainer and you've got one hot near-50-year-old.

She hasn't exactly come clean about it, but anyone with eyes can tell that Ashlee Simpson is sporting a new nose (and hair extensions to boot). Now PopSugar.com is reporting that In Touch claims that Ashlee has also had work done on her eyes and chin.

Though she's virtually unrecognizable from her original self, Ashlee's plastic surgery has definitely improved her appearance. Is sister Jessica quaking in her cowboy boots?

Yeah, yeah, we all know she was "the world's first supermodel." But Janice Dickinson has morphed from a stunning A-list model with the exotic looks of a Jessica Alba or Phoebe Cates to a surgically stretched hot mess. Does she look good for her age (52)? Absolutely. Does she look like the girl that appeared on countless fashion magazine covers? No way.

Not surprisingly, Janice has used plastic surgery to maintain a youthful look, though in the process she's become less "exotic beauty" and more "drag queen." According to CelebrityCosmeticSurgery.blogspot.com, she was recently filmed getting Botox injections, and Dr. Anthony Youn also speculates that she's had bad lip implants as well as some brow work. GoodPlasticSurgery.com also reports that Janice has admitted to getting breast implants.

But don't just take their word for it. BrainyQuote.com quotes this gem from Janice herself: "I'm addicted to cosmetic surgery!"

What a difference a gastric bypass makes. When Star Jones Reynolds first showed up on the scene, she tipped the scales at 300+ pounds. In a personal essay featured in Glamour, she confided that "My weight gain began to take a physical toll: I couldn't breathe without sounding winded; walk without getting tired; sleep without snoring; or take a flight without using a seat belt extender."

That all changed in 2003, when Star underwent gastric bypass surgery. Since then, she's lost more than 160 pounds, had a breast lift, cut her hair, and added glasses. In other words, she looks nothing like her former self.

We love Jennifer Aniston. Really, we do. But the thin, yoga-obsessed, highlighted Jennifer Aniston of today looks dramatically different than the sexy, curvaceous, brunette who first appeared on "Friends." And no, it's not just the hair.

Though Jennifer admits to having her deviated septum fixed last year, she downplayed rumors of other plastic surgery to People, saying, "As far as all the other [rumors], as boring as it sounds, it's still mine. All of it. Still mine. Short of letting everybody have a feel, I don't know what else to do. I really am pretty happy with what God gave me."

TheSnagWire.com doesn't seem convinced, saying, "Jennifer Aniston has evolved from a round-faced brunette girl-next-door into a jaw-jutting blonde diva. Jen played it smart, and got her plastic surgery slowly over time."

Katie Holmes isn't the only Mrs. Cruise to undergo a dramatic transformation. Nicole Kidman used to be an Aussie girl known her for her wild red ringlets and her straight-from-the-farm fresh-faced good looks. Now she's got fluffy blonde hair and a frozen, overly Botoxed forehead. Looks like someone took her role in "The Stepford Wives" really seriously.

AwfulPlasticSurgery.com sums it up best: "People don't find Nicole unattractive; rather they are simply baffled by how different she looks now compared to when she started. Aging is allowable, but looking like a different person is odd." The site also speculates that Nicole has undergone rhinoplasty, a brow lift, cheek implants, lip injections, and Botox.

A rose by any other name may smell just as sweet, but an Axl Rose with red cornrows and a plastic face is anything but. The Guns 'n' Roses frontman still hasn't released his long-anticipated new album, but he has managed to transform himself from a skinny redhead with long straight hair to a bulked-up Bo Derek wannabe with a Botoxed face that has Beverly Hills written all over it. Slash would not approve.

While sites like AwfulPlasticSurgery.com speculate that Axl has also had a facelift and cheekbone implants, we'll let Scott Weiland, who reportedly called Axl a "fat, Botox-faced, wig-wearing" you-know-what, have the last word.

Think the makeover Brittany Murphy's character received in "Clueless" was impressive? That's nothing. In addition to looking almost nothing like her teen self, Brittany also manages to look like a completely different person every time she's photographed. Hair color and cut have a lot to do with this, sure, but we smell a scalpel-wielding rat.

Imdb.com reports that Brittany denies any plastic surgery (she's been rumored to have had collagen lip injections and rhinoplasty), saying, "I have broken my nose three times but I've never had it fixed. I know it changed the shape of it. True beauty comes from within, but if it (surgery) makes you feel better about yourself, go for it."

If ever there were a celebrity (and we use the term loosely) who would never need to join the Witness Protection Program, it's David Gest. The man has more faces than Mr. Potato Head, thanks to a longtime relationship with plastic surgery.

In an interview with Mirror.co.uk, even David's sister admits that he's unrecognizable: "He does not look the same. These days he never takes his trademark sunglasses off even when he is inside."