"The truth is, I have more money than I'm interested in spending," says Sam Simon. "Everyone in my family is taken care of. And I enjoy this." Araya Diaz/Getty

"The Simpsons" co-creator, Sam Simon, is battling terminal colon cancer and has just three to six months to live — but the 58-year-old nine-time Emmy-winning writer-producer is making good use of what time he has left.

Simon, who says he earns nearly "tens of millions" annually off his "Simpsons" royalties, is donating his entire fortune to charity before he dies.

"I get pleasure from it. I love it. I don't feel like it is an obligation," Simon told The Hollywood Reporter in a new interview.

Various charities are the recipients of Simon's generosity — from a dog-rescue haven in Malibu and PETA to Save the Children and the Sea Shepherd Conservation Society.

His Sam Simon Foundation in Malibu is worth $23 million and he feels strongly about shutting down roadside zoos and abusive animal shows.

"I want medical experiments on animals stopped. They don't do anything, and they don't work," Simon said of donating heavily to animal rights causes. "Veganism is an answer for almost every problem facing the world in terms of hunger and climate change."

Simon says that while "I was never that hands-on with any of it [the charities]" he has "been fortunate to find great people to run things."

Not that Simon has much free time. Between doing his own radio show, working on Charlie Sheen's FX show "Anger Management" and chemotherapy, Simon is still keeping busy after co-creating "The Simpsons" more than 20 years ago alongside cartoonist Matt Groening.

Simon has no children and is not currently married but his ex-wife, actress Jennifer Tilly, tells THR, "He really does have a passion to survive, and the longer he's on the earth, the more good work he can do."

"The truth is, I have more money than I'm interested in spending," reveals Simon. "Everyone in my family is taken care of. And I enjoy this."