Scarlett Johansson and her signature red lips.

ScarJo never goes au naturel.

The 27-year-old "We Bought a Zoo" actress revealed in an interview with Style magazine that though she went make-up free for the movie, off screen, she relies on red lipstick - at the very least.

"I like to feel a little more together - you never know who you're going to see out there!," she is quoted as saying in the U.K.'s Daily Mail. "My absolute must-have is a really rich and vibrant red lipstick. I always keep red lipstick in my bag because I never know when I might show up to an event and be completely under-dressed."

"I always like to put a little bit of make-up on," she added. "I'm not the kind of person that just slops around in sweatpants."

Guess we know who won't be lounging around in PJs Christmas morning.