Sam Simon may be best known as one of three men responsible for bringing "The Simpsons" to television, but it's his work beyond that history-making sitcom that will forever define him. 

The 57-year-old announced on the "Leiberman: Live at 5" on Howard 101 radio that he's fighting aggressive colorectal cancer that has metastasized and spread to his other organs. Doctors have given him only a few months to live, but Simon is undergoing chemotherapy nevertheless in an effort to fight back. 

"The diagnosis was--I was feeling bad for a couple years, and I was diagnosing myself from television talk shows, so I was taking antidepressants and I was trying to get my testosterone levels up," he says. "But then it turned out my primary cancer was colon cancer that had spread to my liver, kidneys, abdominal connective tissues and my lymph system and maybe my brain. They're not sure about that."

Since he parted ways with "The Simpsons" in 1993, Simon has become a force in the world of animal advocacy through his self-funded Sam Simon Foundation. The organization is dedicated to rescuing and rehabilitating stray dogs that would otherwise be euthanized. These animals then go on to become service dogs for the disabled. His foundation also offers a free mobile spay and neutering program for low-income pet owners. In 2011, he launched the “Sam Simon Foundation Feeding Families” which provides food for people and animals in need. He’s also a board member for Save The Children, hosts the largest annual fundraiser for PETA (which recently named its Virginia HQ after him), and donated a multi-million dollar vessel to the Sea Shepherd Conservation Society.

Oh yea, he's also a successful professional poker player, former heavyweight boxing manager, and active television producer - with recent directing credits for the FX series "Anger Management." It's no wonder in a 2007 "60 Minutes" profile that reporter Daniel Schron called him "the Renaissance man of the baffling, uncertain age we live in."

Simon says he received his unfortunate diagnosis just before he was about to leave with the Sea Shepherd on their latest anti-whaling campaign in the Southern Ocean. 

"I had all my stuff ready to go for the adventure of my life, but instead I got a different kind of adventure," he says. "I’ve had the greatest life in the world. So, when it comes to talking about disappointments, they’re very high end disappointments, and there's not many of them, but this [missing the trip] would be the biggest one.”

Despite the grim news, Simon sounds relatively upbeat about the whole thing. 

"I don't believe in miracles," Simon added. "And I don't believe in 3-6 months [to live]. I think it's an adventure and we shall see what happens."

You can hear Howard Stern, a close friend of Simon's, play audio of his interview and reveal below. 

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

'The Simpsons' co-creator Sam Simon diagnosed with cancer
Animal activist and philanthropist says he's had 'the greatest life in the world.'