Joanna gaines family photos

Joanna Gaines shares the hobby she and Chip are enjoying together for the first time — and what inspires them to do it

Though they've been married for 20 years, share five kids, and own multiple businesses together, Joanna Gaines says she and husband Chip have only recently added this mutual hobby to their schedules: working out.

"We joke that we've known each other for 25 years and we've never once worked out together," Gaines tells PEOPLE.

Related: All About Chip and Joanna Gaines' 5 Kids

Gaines says having a 6-year-old son, Crew, motivates her to stay fit.

"I told Chip, we need to do something to make us stay strong," Gaines, 46, continues. "And so we just got into this, and it's a totally different thing for us. We've never worked out together before and now we do."

Related: All of Chip and Joanna Gaines' Most Romantic (and Hilarious) Throwback Pics

She says they have a virtual trainer that they meet in their "tiny home gym" on Magnolia Farm in Waco, Texas.

"It's just us Chip gaines!