Welcoming son Cree last summer, Tia Mowry still struggles with her post-baby body -- and is willing to pull out all the stops to snap back into her pre-pregnancy shape.

On Monday's episode of STYLE's Tia & Tamera, mom Mowry, 33, and her twin sister, Tia, turn to to weight loss guru Richard Simmons to shed pounds.

"I didn't want Tia to focus so much on losing the [baby] weight that she'd forget how fun [working out] could actually be," Tamera reasons in a preview clip from Monday's show. "Richard Simmons is the perfect person for that. He works your behind off, but he's so much fun!"

Indeed, the sisters have a ball when they stop by the Sweatin' With the Oldies superstar's fitness studio in L.A. As she laughs her way through the high-energy class, a sweaty Tia is inspired by another gym goer.

"When I see a woman 80 years old doing the same workout I'm doing and she's doing a hell of a job at it, I think 'I can do it, too,' Cree's mama explains. That's what I like about this class."

Watch the clip above for more of Simmons' wacky gym antics before the full episode of Tia & Tamera airs Monday at 8 p.m. (EST) on STYLE.