Justin Timberlake is bringing ‘SexyBack’ and getting shredded. The singer and actor, who recently reunited with his *NSYNC bandmates at this year’s VMAs as well as delivering a creepy performance in the Netflix thriller Reptile, has been putting in some “serious work” in the gym.

According to his trainer Ben Bruno, Timberlake has lost more than 20 pounds in four months, slimming down while packing on lean muscle at the same time. Bruno recently shared a clip from one of Timberlake’s workouts, which shows the star pushing 440 pounds on a sled.

“This is a full-body exercise that requires the upper body and lower body to be *NSYNC, so naturally he crushed it,” wrote Bruno in the caption. “Jokes aside, Justin has been on a mission the last four months, crushing the training and dialing in the diet.”

“He’s taken his bodyweight from 194 pounds down to 170 while getting significantly stronger, which isn’t easy to do,” he continued. “I think it’s awesome that a guy in his position in life puts in such consistent effort in the gym because there truly are no shortcuts when it comes to changing your body. No matter who you are, you’ve just gotta put in the work.”

Bruno is right that sled training is an excellent full-body burner, although Timberlake appears to be focusing more on his upper body and shoulders here, rather than driving the movement with his legs. However, he is bracing himself with a strong starting position.

In addition to Timberlake, sled pushes and pulls are a strength-building staple favored by NFL pros James Harrison and Alvin Kamara, and swole celebs like Mark Wahlberg and the Hemsworth brothers.

Why not try ‘Rock Your Body’ and try this challenging exercise for yourself?

Philip Ellis is News Editor at Men’s Health, covering fitness, pop culture, sex and relationships, and LGBTQ+ issues. His work has appeared in GQ, Teen Vogue, Man Repeller and MTV, and he is the author of Love & Other Scams.