The German-born supermodel left the fashion reality TV series with co-star Tim Gunn eight years ago, with the two going on to launch a rival fashion competition show, “Making the Cut,” on Amazon from 2020 to 2022. Now Klum, 52, has returned to her best-known TV role, stepping back onto the “Project Runway” stage via a giant zipper entrance on the set in its new home on Freeform, Disney+ and Hulu. Her co-star for the 21st season, which premiered in late July, is designer and season four winner Christian Siriano.

Klum’s career hit warp speed after she appeared on the cover of the 1998 Sports Illustrated swimsuit issue. Soon, she was strutting down a televised Victoria’s Secret runway wearing a $12.5 million bra. Her career as a TV personality took off with “Project Runway,” which won her an Emmy in 2013. She is a host, judge and executive producer on that show and the long-running series “Germany’s Next Topmodel.” Her reality TV résumé also includes stints as a judge on “America’s Got Talent.”

A mother of four whose youngest is now 15, Klum lives in Los Angeles with her husband, German musician Tom Kaulitz. Here, she talks about how changing clothes is a valid form of exercise, what professional project she considers her baby and whether her body might be harboring worms, parasites or both.

What time do you wake up?

At the moment, I wake up at between 4 and 5 in the morning, just because I’m extremely jet-lagged. But normally I would say around 6 and then I just putter around. I just finished shooting “Germany’s Next Topmodel.” I did that for three-and-a-half months. If I go to work, I get in the car and go wherever we’re shooting. Usually I will eat something there, then I start hair and makeup for two hours, and then I pretty much shoot all day and try to be back home for dinner, which is at 7 p.m.

What is your coffee routine?

I try to not have real caffeine, otherwise I get too jacked up in the morning and that’s not good for me because I’m already busy doing 5,000 things at one time. So I drink decaffeinated coffee in the morning with milk and sugar. Blonde and sweet, just like me.

And do you exercise?

I feel like I exercise every day because I don’t sit around on the couch. I’m always moving, doing things. I don’t have someone that packs and unpacks for me. I run thousands of errands. Today, for example, I have a fitting, then I try on I don’t know how many outfits. It’s clothes on and off, on and off, on and off, on and off. So I feel like I exercise kind of all the time. Then we have a pool at home, so I swim a little bit in the pool. And we have a trampoline.

Do you jump on your trampoline?

I haven’t done it in a while. We have a real professional trampoline built into the ground. I have four kids, and when they were younger, that was their favorite thing to do—go in the pool and go on the trampoline. I used to be really good at it, where I would just land on my butt with straight legs. I could flip in the air and go on my legs again.

Do you follow a special diet?

I don’t. I’m going to deworm and de-parasite for the first time. Everything I’m getting on my Instagram feed at the moment is about worms and parasites. So I’m doing a worm cleanse and parasite cleanse with my husband. I heard that you’re supposed to do this once a year, and I’ve never done it. So I feel like I’m really behind. I don’t know what the heck is going to come out.

Is there any evidence that you have worms or parasites?

Apparently, we all have parasites and worms. If you are someone who eats raw things every now and then, like, for example, sushi. There are pills [to get rid of them], they have all of these herbs. There’s a lot of clove in there. The parasite hates clove. They also hate the seeds from a papaya. We have all this metal inside of us, and it’s also very important that you use this de-metaling stuff.

Do you feel any better?

I’m starting this now, and you have to do this for months. It’s like a whole thing.

What made you decide to return to “Project Runway”?

“Project Runway” is my first television baby. It’s something that I have helped create, help sell to the network that ended up choosing us at the time. I love the show. I’m proud of the show. I feel like we’ve come a long way. We talked about important things on the show that were kind of groundbreaking, I thought, at the time, including body positivity. So I feel like, “Yes, I’m coming back.” But you know, in my heart, I was never really gone.

And why did you step away from “Making the Cut”?

It was very expensive to make. Ultimately, it’s not always the talent’s decision. I was an executive producer, but it was not my personal money that was spent. The winner got a million dollars. It was a different level of production. So, yeah, things come and go in life.

Some critics called “Making the Cut” too much of a promotion for Amazon shopping. What did you think?

I always thought that it was good to make [fashion] for everybody, so that it’s available around the world. And it kind of brought everyone closer together. If you live in Los Angeles, or you live in New York, and you can go to the cool stores, that’s one thing. But if you live in the middle of nowhere, you watch this and you want this item. I’ve tried to do something so that the viewer, the customer, so to speak, can also buy into what the designers are making. I always loved when on “Project Runway” we had challenges where it was then available for people to buy. That was the ultimate cool thing.

This interview has been edited and condensed for clarity.

Write to Ellen Gamerman at [email protected]

Heidi Klum Is Starting a ‘Worm and Parasite Cleanse’ © Disney

Heidi Klum says she drinks decaffeinated coffee in the morning with milk and sugar. ‘Blonde and sweet, just like me,’ she says. © Disney

Klum has returned to “Project Runway.’ ‘In my heart, I was never really gone,’ she says. © Disney

Klum says she’s doing a worm and parasite cleanse with her husband, German musician Tom Kaulitz. © Andreas Rentz/Getty Images