The `Water for Elephants` actress - who is engaged to Hollywood agent Jim Toth - hates to be caught without her favourite cosmetics, though she insists she tries to limit what she takes with her.
She said: "I have a bunch of different make-up bags - one in my car, one in my handbag and one at home.
"I try to keep them small, but I have about five lipglosses, mascara, cover-up, lipstick and blush."
One of the things the actress relies on keeping in her make-up bag is a white eyeliner pencil, as she believes it keeps her looking refreshed.
Asked for her best beauty tip, she said: "Put a little white eyeliner in the centre of your inner eye when you`re tired. It makes your eyes look awake!"
Reese - who has children Ava, 11, and Deacon, seven, with ex-husband Ryan Phillippe - also admits that she takes more care of her appearance now she is getting older.
The 34-year-old beauty told Britain`s Glamour magazine: "I`ve always used moisturiser and SPF, but as you get older you really have to take care of your skin - you must take off your make-up and put on your moisturiser."