Entertainment executive and investor, 41
Why it's new: If you think plaid shirts are just for lumberjacks, hipsters, and your husband, think again. Fall's versions are refined and office appropriate.
How she wears it: A former music executive, Ellis helped shape Beyoncé's and Mariah Carey's careers before launching a branding company and becoming a founding partner at an investing firm. An avid equestrian, she likes pieces that can take her "to work, to the barn, and to dinner," she says. She pairs her plaid shirt with trousers, a belted cardigan, and a splashy hat. "I want to look fashionable, not like I'm wearing a business uniform."
Why you should try it: Plaid, when used correctly, is a fresh twist on office casual. "A plaid shirt with a more tailored item, like these beautiful trousers, looks put together but not overly serious," says Ellis.
Adam's Tip: When wearing menswear-inspired pieces, add feminine touches—like metallic heels—to avoid looking "too Annie Hall." And when mixing plaids, "keep colors in the same range."
Shirt, CK One, $50; Select Macy's stores; 800-622-9748. Belted sweater, NSF Clothing, $380; NSFClothing.com. Trousers, Chadwick Bell, $1,280; Bergdorf Goodman, NYC; 212-753-7000. Hat, Andean Collection, $69; TheAndeanCollection.com. Bracelets, Harriet Anthony Jewels, starting at $2,200 each; 212-334-1160. Clutch, Salvatore Ferragamo, $1,550; 800-628-8916. Shoes, 3.1 Phillip Lim, $795; 212-334-1160; Shopbop.com. Watch, Michael Kors, $180; MichaelKors.com.