Jane Seymour has one surprising fitness confession at 75.

Seymour relies on a routine that’s kept her energized for decades — one that’s built on movement, moderation and knowing her limits.

The “Harry Wild” star said she avoids yoga because she’s “way too A-type,” joking that she’d try to outdo everyone in class.

“Well, fitness, I try to do a combination of light weights, some walking, fast walking if I can, or up and down a hill. I do Pilates and Gyrotonics, or if I can’t do any of that, I do the usual thing, the sort of sit-ups and some ballet exercises,” she told Fox News Digital.

“Actually, I go back to my ballet roots. I do a full barre. I eat a Mediterranean diet, usually. I stay away from starch, but not completely, because I never want to think I’m on a diet. I drink very moderately. When I’m filming, not at all.”

Seymour said the secret to staying active isn’t pushing herself to do every trendy workout — it’s knowing her own limits.

“I’ve had to actually tell myself that when I go into a group class, especially something like yoga, that I have to tell myself I am not going to win, because I’m way too A-type…”

She continued, “I want to win… Which means that I can never have done yoga, and I will decide that I could turn myself into the pretzel like that person. No. No, I cannot. I’ll end up in the hospital or something, so… My approach is to try everything, but do it the way that I know I can. So, I listen to my body.”

That mindset has helped fuel Seymour’s seemingly endless energy — something her longtime friend and former “Dr. Quinn, Medicine Woman” co-star Joe Lando knows all too well.

More than three decades after becoming one of television’s most beloved couples, the pair have reunited for Season 5 of “Harry Wild,” which returns to Acorn TV with bigger mysteries, higher stakes and a new character who could finally complicate Harry’s love life.

Seymour stars as Harriet “Harry” Wild and also serves as an executive producer on the hit show.

Their on-screen reunion is rooted in a friendship that’s outlasted Hollywood odds. 

When Fox News Digital asked how they’ve stayed close all these years, Seymour reflected on the bond they built while filming the hit Western drama.

“Wow, I mean, that’s a really interesting question,” she said. “We worked together for seven years and we kind of fell for one another in the pilot, rather famously, for a brief time. So, we knew each other really, really well, better than on screen.”

The pair eventually realized they were better off as friends, but Lando said one thing about Seymour has remained exactly the same since their “Dr. Quinn” days.

“This inexhaustible flipping energy,” he said. “She just goes, goes and goes.”

Comparing Seymour to the Energizer Bunny, Lando recalled filming long production days while the actress was pregnant with twins.

“45, pregnant with twins. We’re doing 12-hour-plus days sometimes,” he said. “I’d start feeling myself getting a little worn, and I would look over at her… suck it up, get out there and do the job. And that hasn’t changed about her.”

Seymour credits her seemingly endless energy to one simple thing — loving what she does.

When asked where her legendary stamina comes from, Seymour didn’t hesitate.

“I know people keep asking me why, and I just say, because I love what I do,” she said. “I just do, you know, and then when I stop, I sleep.”

AMC Global Media’s “Harry Wild” Season 5 streams exclusively on Acorn TV.