Exclusive! Get the Most Badass Brows of Your Life With MAC's New Line

"Her brows are pretty dramatic . . . you can tell they're painted on, but that's the look," said Roberts, who recommends a very durable, longwearing formula for this style of arch. "If you get caught in a rainstorm, you don't want them melting down to your eyelashes!" he joked.

To re-create Katy's brows, try MAC Cosmetics Veluxe Brow Liner ($21, available in 10 shades). Though it's a pencil, the formula has a unique texture that makes it almost like a powder in a stick. This provides the precision of a pencil but the opaque application of a brow powder, creating a matte, velvety finish. The fine particles cling to the teensiest hairs and plump up sparse arches, but don't fade or sweat off. Bring this product on your next tropical vacation!