The 33-year-old Still Alice star appears flawless when gracing red carpets at parties and premieres, but at home she uses Aczone to zap her zits.

"This product is preventative," she tells "It takes 12 weeks to even start working; it's not a spot treatment, like something you see at a drugstore. You don't use it to get rid of zits, you use it so you won't get them at all."

The actress blames "travel and erratic sleep patterns" as well as "hormones" for the unwelcomed breakouts, and she accepts her diet doesn't help, noting: "For me, it's really refined sugar and booze (that causes breakouts). There's a doctor I work with in London who's a gastro-entomologist who's combined the beauty with actual knowledge of the gut. And sugar corresponds to certain glands in your face.

"So when I drink wine, I'm like, 'Yep, there's a wrinkle right there'. Which doesn't mean I'm not drinking wine. Or vodka. Or tequila."

The star is also unwilling to give up eating cheeseburgers at some of her favourite fast food chains, but she does impose restrictions on her diet when she is on set shooting a film or TV project.

"So my rule is, when I'm working, I'm diligent about what I'm doing with my body," she explains. "I'm not going out for a wild night. I'm not eating a rich crazy meal. If I do those things, I won't wake up early ready to work. I can't do it anymore. When I was 22, sure. At 33? I can't. But on the weekends, we're going to Five Guys (burger restaurant).

"I love Five Guys. Shake Shack's my favourite, but there's a Five Guys around the corner from us in Montreal where we're filming. Oh, and when you eat Five Guys? You have to be guilt free. You go all in."