Duff and Walsh worked out for a charity event supporting victims of Hurricane Harvey
Credit: Xxplosive/PressPhotoBank /Splash

Hilary Duff spent Labor Day soaking in the sun with her ex-husband and son.

Duff, 29, and Mike Comrie, 36, were photographed playing on the beach with Luca, 5, on Monday. The Younger star rocked a black bikini that showed off her toned body — a day after working on her fitness (for a good cause!) with ex-boyfriend Jason Walsh.

Credit: Xxplosive/PressPhotoBank/Splash

Duff and the personal trainer split last fall but hit a gym in West Hollywood together on Sunday. It turns out the two shared a sweat session at Rise Nation fitness center to benefit victims of Hurricane Harvey: the singer posted an Instagram of a group, including Walsh, promoting their cause.

“There was no option but to turn this photo black and white. I was literally purple this climb was so hard and it was so hot!” she captioned the snapshot. “Charity climb for the land that I love #houston @risenation 🙌🏻💪🏻❤️.”

Duff was linked to Ely Sandvik in July, spending another beach day with the EO of SOLr Energy Consulting.

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As for her relationship with Comrie? The former couple has remained committed to co-parenting ever since separating in 2014 after nearly four years of marriage. (Their divorce became finalized in 2016.)

“Some of my friends tell me, ‘God, it must be so nice, you get a break from your kid because you share him.’ I’m divorced, and it sucks,” she told Redbook in April. “Well, it did suck for a while; now it’s just normal.”