Twenty Most Unbelievable Transformations

This Joker manages to make people forget all about Nicholson (and Romero) by bringing an even scarier smirk to the Batman franchise.

Bale was intense even before becoming Batman. He starved himself for four months to play a chronic insomniac.

Downey earned an Oscar nod for playing an Australian actor playing an African-American G.I. in a Vietnam War movie.

Pretending to be an old British woman is a small price to pay for a devoted dad hoping to spend some time with his kids.

In Tim Burton's Batman, Nicholson made people forget Cesar Romero's campy Joker by dancing around to Prince in a pimp suit.

Norton went from buff tattooed Neo-Nazi to slightly less buff, tattooed ex-Neo-Nazi trying to make amends.

From Fedex exec to rugged, ragged survivalist, Hanks maintains his sanity during his change with the help of a friend: Wilson the volleyball.

As a man with a head so large he could've been a modern news anchor, Hurt famously tells the world, "I am not an animal!"

In real life, he stole Jenny McCarthy's heart. In this movie, he become the titular green grouch and takes Christmas away from Whoville.

The method actor tricks everyone into believing he's a soap star, even though he looks like a menopausal hobbit.

The upside to becoming The Fly? He could have sex for hours on end. The downside? He had to regularly eat his own vomit!

Is that you under there Billy? As the healer Miracle Max, Crystal dons so much makeup he's indistinguishable from his hideous wife. 

Murphy liked donning a fat suit so much in The Nutty Professor that he went back and did it again a decade later in Norbit (2007).

In Grease he sings and dances. In Hairspray, he does all that and dresses up as an obese agoraphobic woman. What's next?

Before he was a Grumpy Old Man, Lemmon was an ugly woman on the run, putting on his skirt one leg at a time.

Davidson's female gender-bender is so fetching, the hero eventually gets over the realization that she is a he!

Leto did what he had to do to play John Lennon's portly assassin. Namely, gaining almost 70 lbs by drinking microwaved ice cream.

Unlike the Grinch, another beloved Seuss character, this rhyming cat in the hat will never, ever be back.

It's hard to believe that the star of Pulp Fiction would get so lost in space, but this Scientology-tinged turkey nearly spun him out of orbit.