It's actually less of a "thing" than a person.

Modern Family star and mother of three Julie Bowen, 43, told Lucky Magazine she and Kristen Stewart, 22, share the same stylist.

“It was a big evolution in style for me to grow up and say ‘I need to take fashion seriously for my job,'" Julie said (via In Touch Weekly).  

"I have a stylist now, and she’s trying to get me to wear more revealing stuff. She’s Kristen Stewart’s stylist. ... I go [to my stylist] and see all this amazing funky stuff, and I know it’s for her. If I get KStew’s castoffs, that’s all right with me.”

Kristen tends to go for an edgy look at many red carpet events, although we know she loves to just wear T-shirts and sneakers most of the time. If we start seeing Julie wandering around in backwards baseball caps and Robert Pattinson's old shirts, we'll really know she's wearing KStew's castoffs!

Source: In Touch Weekly