The supermodel’s spilling her secrets.

Miranda Kerr, 42, has been outspoken about her holistic wellness routine. She’s even became a certified health coach and launched her own skincare line, Kora Organics.

And she recently told The Post about the pricey tool that tackles multiple issues across her body — plus the totally free practice she considered “one of the most underrated beauty secrets” there is.

Her splurge? Red light.

“I’ve been loving red light therapy,” she said, adding that she prefers to get it from a light mat that can target lots of places at once.

“It uses red and near-infrared light to support everything from skin rejuvenation to muscle recovery and nervous system regulation. It’s amazing how much of a difference it makes — not just to my skin, but how I feel in my body.”

Early research shows that red light therapy can also reduce inflammation — a main cause of proctitis, a form of IBS that Kerr opened up about having last year.

“It’s an autoimmune thing and they don’t necessarily have the answers to why, which is frustrating,” she told Get the Glossshe explains.

It’s also been shown to reduce pain caused by inflammation, including rheumatoid arthritis and carpal tunnel syndrome.

For skin, proponents say it can reduce wrinkles and stretch marks, fight discoloration and sun damage, help with acne and even combat skin conditions likes eczema and psoriasis.

Some other ways to combat wrinkles and other signs of aging? Daily SPF, plus the star’s other top skincare rules.

But not all of Kerr’s wellness tips and tricks are worth a fortune. In fact, one of her favorite things won’t cost you a thing.

“Honestly, one of the most underrated beauty secrets is nervous system support,” she said.

“Simple things like Vedic meditation, deep breathing, or putting your bare feet on the earth help your whole body find balance,” she went on.

“When your nervous system is calm, it shows — in your skin, your mood, your energy. That inner harmony really is the foundation for outer glow.”