The DNCE lead singer, 27, showcased an impressive six-pack and defined arm muscles during a personal training session in Beverly Hills, California.
The middle Jonas brother was seen wearing athletic shorts and boxing gloves while working up a sweat in a public park.
The musician seems to be on a fitness kick that is clearly paying off. Last week, Jonas posted a photo to Instagram of his muscular back while working out at a Chicago-area gym.
He’s also been lifting heavy weights and boxing as part of his workout regimen.
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Keep up the good work, Joe!