Oprah: That's what's so incredible.

Charlize: I never questioned it, because transformation is just what I do. I like to get into the makeup, the hair. When I saw Patty two weeks ago, we were laughing because the whole thing happened so organically. We built teeth and played around with contact lenses.

Oprah: So were you instrumental in deciding how the character would look?

Charlize: Yes. Toni G, who did the makeup, played a huge part, too. She has this incredible eye. You can't just take a mask of somebody and put it on someone else. You have to manipulate the features of the actor. She really transformed my face. We'd play around in my kitchen...

Oprah: This kitchen, where I just sat and had the nice potatoes?

Charlize: Yes. We were filing down false teeth. Patty and I were actually like, "Do you think it's enough?" By the time we began the makeup and hair tests, we'd gotten so used to my [new] face. I stayed in it most of the time while I was on set. I would wear Aileen's clothes all the time, have my hair the way she would, so the crew really got to know me as Aileen.

Oprah: Didn't you have to get hours of makeup every morning?

Charlize: No. The whole thing took just under an hour.

Oprah: That's right—because you'd put on all that weight.

Charlize: The only prosthetics we used were on my eyelids, to make them heavier. Everything else was handpainted and airbrushed. Then I'd pop in the teeth and put in the lenses. I didn't do anything with my hair. I would wet it in the morning, then comb it back and let it dry that way.

Oprah: I'm sitting here looking at your luminous skin. How did they change that?

Charlize: They put an alcohol-based liquid on my face and dried it with a blow-dryer. It made my skin look leathery and sun-damaged. But I never felt ugly.

Oprah: I didn't think Aileen was ugly. I just thought she was different from you. Did you make a conscious effort to gain 30 pounds?

Charlize: No. I just thought, "I'll see how much I can gain."

Oprah: What a delight. Dear God in heaven!

Charlize: It was over Christmas, so it was perfect. I finished everybody's desserts.