Credit: Splash News Online

Don't let this one go, Jennifer Aniston! The star's fiance Justin Theroux worked up a sweat jogging in a short-sleeve sweatshirt and loose sweatpants while shooting his new TV movie, The Leftovers, in Queens, NYC Wednesday, June 26. One accessory missing from the hunky actor-writer's on-screen ensemble? Underwear.

With earbuds firmly in place, Theroux, 41, inadvertently channeled Jon Hamm during the intense cardio scene -- revealing a very noticeable outline of his, er, anatomy as he ran. (Based on author Tom Perrotta's novel of the same name, suburban drama The Leftovers also stars Liv Tyler and Christopher Eccleston.)

Mad Men star Hamm, of course, sparked endless internet chatter and memes after he was repeatedly photographed going commando, with photographers capturing eye-popping shots of his crotch. "They're called 'privates' for a reason. I'm wearing pants, for f--k's sake. Lay off," he complained to Rolling Stone. Still, he reasoned, "There are harder jobs in the world. But when people feel the freedom to create Tumblr accounts about my c--k, I feel like that wasn't part of the deal [of fame]."

Theroux and Aniston, meanwhile, have been laying low -- having recently put their wedding plans on hold. "She has been cranky from this stress," an insider told Us of the 43-year-old actress, who's been busy with multiple film projects, endorsement deals and a massive renovation of the couple's $21 million Bel-Air home. "Justin's never seen her like this."