Sylvester Stallone reveals surprising health struggle behind his famously ripped physique

While prepping for his role in the 1982 movie "Rambo," Stallone - who has authored a new memoir, titled "The Steps" - said he took pains to appear more "animalistic," drawing inspiration from jaguars and cats.

"Then it became an obsession. Really bad. It got to the point where I became bulimic," he said during the interview.

Stallone also admitted that he took steroids during some time periods. "You have to," he said. "But you do it in a sensitive way - six weeks on, six weeks off … that also took a terrible toll."

"I've abused my body," he said. "Everything is held together with baling wire, but I still want to stay in good shape."

"All of a sudden, I stood up and the hair on my neck went up and I started getting hot and I go, 'I'm dying, this is it, I'm on my way out,'" he said in the interview.

The actor said the panic attacks happened "again and again and again," often resurfacing before high-profile television appearances. As he aged, Stallone continued to experience anxiety and sometimes felt compelled to leave crowded rooms.

"The idea that a man enhances his appearance to remain consistent with his own public image and internal comfort goes back decades - [Stallone] isn't the first, and he isn't the last," Pollack said.

"He has to almost keep himself in this homeostatic state where people expect Sylvestor Stallone to be Rocky, which is his quintessential role," he went on.

"And through his career, one could surmise the need to be able to put all of that together and keep it consistent as he goes through the development and life cycles of maturation, not only in his brain, but also in his body."

Giulia Suro, a licensed clinical psychologist and certified eating disorder expert at Monte Nido in Washington, D.C., added that the Sylvester Stallone revelation was a "game-changer."