“King of All Media” Howard Stern is worth $600 million but when he comes home to his beautiful wife, Beth, he’s on his hands and knees — cleaning up cat litter and fur from their dozens of rescue animals.

The couple have so far fostered more than 300 cats and kittens in the past three years alone in their Upper West Side apartment and Hamptons home.

“He’s the one who wants us to foster more cats even after I say no. Howard helps me socialize the kittens and he has been known to clean litter boxes. The kittens love his hair!” Beth Stern says.

“Sometimes,” she adds, “I get jealous when he’s not listening to me but loving the cats!”

It may come as a surprise to those who know Stern just from his raunchy Sirius XM radio show that “Howard was always a huge animal lover — but marrying me has taken it to a whole other level,” Beth says.

“Our blind resident cat Sophia is madly in love with Howard, and as soon as she hears his voice when he comes in the door, she runs to him. They have a special game they play every day with a toy mouse on a string. He always drops what he’s doing to play with her. It’s so sweet.”

Gorgeous Beth, 44, was always concerned about saving animals, even while working as a child model at age 9 in her hometown of Fox Chapel, Pa.

She attended the University of Pittsburgh, where she majored in English literature.

“I wanted to be an English teacher,” she said. But Elite New Faces from New York came scouting for local talent, and invited her to New York.

Modeling took her to Paris, Greece and Germany. She was soon cast in films like “Flirting With Disaster.” But, she says, “I would never consider myself an actress. I am a horrible actress.”

When she was 26, single and living in New York, she met Howard, the man of her dreams, at a dinner party at Mercer Kitchen. They married in 2008.

“I was always an animal lover,” she says. “I grew up with rescue dogs, cats, guinea pigs and chickens.”

“He knew how important animals are to me and how strongly I feel about rescuing animals and saving lives. Howard is my partner in this in every way.”

For more than a decade, Beth has been volunteering for North Shore Animal League America. She is now their national spokesperson.

‘Our blind resident cat Sophia is madly in love with Howard, and as soon as she hears his voice when he comes in the door, she runs to him. They have a special game they play every day with a toy mouse on a string.’ - Beth Stern

“We are saving lives — and there are so many more to save,” she said.

The Sterns are currently funding an expansion of NSAL, in the name of Bianca, their 10-year-old English bulldog who died in 2012.

Howard once said that Bianca “completed” them as a couple. Now they are creating Bianca’s Furry Friends Feline Adoption and Wellness Center — 14,000 square feet of cage-free living. Rachael Ray and Billy Joel each donated $1 million to the center.

Beth is also hosting her fourth annual Kitten Bowl for Hallmark Channel, which airs before the Super Bowl. One hundred cats and kittens are up for adoption that day, and “we find homes for all of them,” Beth said.

She also hosts the American Humane Association’s Hero Dog Awards. Last year, her co-host was James Denton. The show, on Hallmark Channel, leaves her in tears.

“There’s not a dry eye in the audience,” she says.

As far as the rescue animals the Sterns take into their home, “Howard names them,” Beth says — like Honey Nut and Cheerio for two kittens that they wanted to keep together. And after seriously vetting adoptive families, Beth delivers the cats and kittens to their new homes.

“I’m really good at matching cats and kittens to their ‘forever families,’” she says. She just matched Jerry Seinfeld and his family with a foster kitten. Now she’s looking for Rosie O’Donnell as well as David Burtka and Neil Patrick Harris.

Fostering, she says, has brought a depth to her own life that she is thankful for.

“I don’t have any human children. But I do have pets and fosters. I don’t need to be a mother, but I do need to be saving lives in this way. I am so thankful to be able to do this. I only wish I could do more.”

While fostering cats and kittens is rewarding, it’s not always glamorous. Despite their immense wealth, Beth says she is often scraping cat excrement off the walls “with her fingernails.”

“We are up from 4 a.m. to 11 p.m. cleaning litter boxes,” she said.

Cats also serve another purpose in the Stern household.

“Whenever Howard comes home from work super stressed, he goes into the foster room for 10 minutes and he comes out a different person. It’s a magic potion to happiness and bliss. Everyone should have a pet.

“People ask why I’m always smiling. It’s because I have Howard, and I have my animals,” she said.

And while the cats can sleep “wherever they want,” some of the furry felines often end up snuggling in bed with the couple, she says.

The Sterns currently have six resident cats at home and are currently taking care of seven fosters, including Tiki, which Howard has talked about on his radio show.

“She’s only 1 pound and she was found with a rope tied around her neck tied to a tree branch,” Beth says. “Someone found her after three or four days and brought her to North Shore Animal League, and now she’s our foster, but my friend may adopt her from us this week.”

At one point, there were 19 cats in their Hamptons home — taking up every guest bedroom and bathroom. (”Is that even legal?” she jokes.)

And when their celebrity friends come over for dinner, they also spend time with the foster cats — and often end up adopting at least one or two.

“Robert Downey Jr. came over for dinner, and he named some of our cats, like Ginger and Chaplan,” she said.

‘Whenever Howard comes home from work super stressed, he goes into the foster room for 10 minutes and he comes out a different person.’ - Beth Stern

For the past four years, Stern has also worked with the Wildlife Rescue Center in the Hamptons.

“I took a course on how to rescue and transport injured wildlife. Howard is my driver when I rescue an injured animal,” she said.

So far, Beth has rescued seagulls, turtles and small birds.

“There was a seagull trapped in fishing net wire. He was so dehydrated. I rescued him with my kit, and nursed him back to health. Then Howard and I went back to the beach and released him. He flew up into the sky and about 50 seagulls came out of nowhere to follow him. It was the most beautiful moment — one that I’ll always remember.”

At a Thanksgiving dinner shortly after the seagull rescue and release, the Sterns looked at the turkey, served tableside, and then they looked at each other. “That’s when we became vegetarians,” she said.

But not all rescues are so magical.

“Howard was with me once when we rescued this tiny rodent we saw in the Hamptons. It was suffering, so we took it to the animal rescue center. We found out it was a vole. When we learned its name, we looked it up — and it turned out to be one of the worst rodents ever. One story named the top 10 ways to kill the ‘most annoying’ garden-destroying rodent ever. And here we were rescuing one!”