It's safe to say that peplum details have quickly become something of a wardrobe mainstay. Just look to Jessica Chastain to see how the trend can transform the most basic pieces with its polished, feminine touch. While promoting Madagascar 3: Europe's Most Wanted in NYC, the actress stepped out in a sweet collared, cutout peplum top and satin shorts by Carven. She perfected her chic day ensemble with a pair of nude Brian Atwood heels (for mile-long legs!), then finished with understated studs and glamazon shades. Seeking the same ladylike play on casual wear? Shop our editors' picks to channel Jessica's sophisticated and totally on-trend vibe.