By Sharon Clott Kanter
Updated May 28, 2013 @ 3:00 pm
Bob Benson
Credit: Michael Yarish/AMC

Week after week, we chat with Mad Men costume designer Janie Bryant to get the inside scoop on what Joan, Peggy, Betty, Megan, and the ladies of the show wear each episode. But this week, there's someone else who caught our eye: Bob Benson (played by James Wolk) and his short-shorts swim trunks. That's why we called Bryant to find out the story behind the fish-covered beach gear. "They were a vintage pair that we found at one of the costume shops and we rented them," Bryant told from her Los Angeles home base. "Bob is whimsical in his own way, and I always wanted him to wear colors that were always just a little off. I felt like that was just part of his personality. He’s always saying these funny quirky lines and has this funny way about him, so I loved the idea of him having colors that were just a tad... off. You do get a sense about him that he’s very much the overt the people-pleaser. He’s really fun to dress." And fun to watch, too! Mad Men fans kept Tweeting about the shorts throughout the show, which prompted Wolk to respond: "Soaking up the sun in Bob's too short shorts." Bryant added: "You've got great legs." Agreed!

Click to get more behind-the-scenes costume info, straight from Janie Bryant.