Richard Simmons is an American fitness icon. He’s worth over $15 million. He weighed 269 pounds at his high school graduation. He lost 123 of those pounds in his 20s. He is estimated to have helped Americans lose over 12 million pounds.

And he’s been missing for 1,095 days.

The podcast about his disappearance is #1 on the iTunes charts.

Since 2014, Simmons, now 68, has not been seen in public.

For decades, he courted constant media attention and bathed in the spotlight. He was a regular guest on “The David Letterman Show,” taught his loyal followers at weekly exercise classes at his Slimmins gym in Beverly Hills, California, and made hundreds of phone calls a week to Americans struggling with their weight.

“I don’t have a lot to offer to one person. I have a lot to offer to a lot of people,” he once famously said.

Dan Taberski was one of those people. He met Simmons while attending one of his famous exercise classes in LA in 2012, and they struck up an immediate friendship, as Simmons did with many of his clients.

They were friends for about a year — Taberski has been to Simmons’ house for dinner and the pair even discussed producing a documentary about Simmons’ life — but one day, Simmons just didn’t show up to teach his exercise class. And he stopped answering Taberski’s phone calls.

The following week, Simmons still didn’t show up to class. When he failed to turn up the week after, people started to get worried.

Friends tried calling, texting, driving to his house and knocking on the door. But they found nothing. It was just so out of character.

“He would wake up at 4 in the morning and reach out to 30, 40, 50 people with phone calls and emails,” Taberski told Yahoo News. “It was sustained relationships that lasted years, sometimes decades.”

“[Simmons] changed fitness forever. Before he came on the scene, fitness and aerobics was for people who had hard bodies and just wanted to get a little harder,” Taberski said.

“He remembered because he was overweight himself once that it’s really about the people who live in America, regular people.”

So why would he suddenly give all that up?

Taberski has set out to find the answer to that question in his new podcast, “Missing Richard Simmons.”

The first episode premiered just two weeks ago, and already the series has shot straight to the top of the iTunes podcast charts. It’s been dubbed “the new ‘Serial,’” the blockbuster podcast from Sarah Koenig and the creators of “This American Life.”

Taberski speaks to Simmons’ friends and the people closest to him and tries to figure out what on earth happened. Only three episodes have been released so far, and from those emerge three possible theories:

He had an operation on his knee to repair a decades-old injury and is taking time to recover. His 17-year-old dog died and he is mourning that loss. His live-in housekeeper of 27 years, Teresa Reveles, is controlling his life and holding him hostage.

No. 3 is obviously the juiciest, so let’s explore that.

The allegations against Reveles were made by Simmons’ former masseur and assistant, Mauro Oliveira. In April 2014, 13 months after the pair had met and become fast friends, Simmons said they needed to talk.

“I just want to be by myself, and I want to be in the house, and we’re never going to see each other again,” Simmons told Oliviera, according to the New York Daily News.

“Let’s talk it over,” Oliveira said. “I want to sit here, and make sure you’ll be OK. Let’s go upstairs, I’ll give you a massage and relax you.”

Simmons called up to Reveles, the housekeeper, to let her know they were going upstairs. “Mauro is going upstairs with me,” he said.

“No, no, no!” Reveles shouted, according to Oliveira. “Get out! Get out!”

Simmons told Oliveira he needed to leave. “Is she controlling your life now?” Oliveira asked. “Yes,” was all Simmons replied.

“I feel that Richard is now being controlled by the very people that he controlled his whole life,” Oliveira told the New York Daily News.

“Controlled in the sense that they are taking advantage of his weak mental state. Controlled in the sense that they are controlling his mail, controlling his everything.”

But Simmons’ manager Tom Estey has denied those allegations, telling People his client is safe and simply out of the limelight.

“As I have stated in the past, these claims are untrue and preposterous,” Estey said.

“Richard, after 40 years of being in the spotlight, is now simply taking a break from the public eye and working behind the scenes to continue to help those millions of people worldwide in need of his assistance and on several projects to be announced soon.”

The last time Simmons made a public statement was in March 2016, during a phone call with the “Today” show.

“No one is holding me in my house as a hostage,’’ Simmons told “Today”’s Savannah Guthrie in a phone interview.

“You know I do what I want to do as I’ve always done, so people should sort of just believe what I have to say because, like, I’m Richard Simmons!

“You know, I had hurt my knee, and I had some problems with it, and then the other knee started giving me trouble because I’ve taught like thousands and thousands of classes, and you know right now I just want to sort of take care of me.”

Speculation that Reveles is manipulating him is “just very silly,” Simmons said.

“Teresa Reveles has been with me for 30 years,” he said. “It’s almost like we’re a married couple.”

Taberski says there has been “some stirring” from the Simmons camp since the podcast launched, but he has yet to talk to the man himself.

“I’m hoping to end the podcast with a conversation with him,” he told Yahoo.

“This is my grand gesture to Richard. I want him to see that we don’t see him as a one-dimensional person, that we understand how important he was, and that he’s loved.”