Stephen Hawking, Legendary Physicist, Dead at 76

The news of the acclaimed scientist and best-selling author's death was announced on Tuesday.

British theoretical physicist Stephen Hawking, author of the acclaimed best-selling book A Brief History of Time and the subject of the 2014 biopic The Theory of Everything, has died.

Hawking was 76.

A spokesperson for the celebrated scientist's family confirmed the news of his death to CBS News Tuesday evening.

Hawking was born in Oxford, England on Jan. 8, 1942. When he was 21, and studying to get his Ph.D from the University of Cambridge, Hawking was diagnosed with Amyotrophic Lateral Sclerosis (ALS). Doctors told Hawking that he had only a year or two to live.

Hawking didn't let that deter him from his ambition and he continued on to become one of history's most famous minds, even as his body deteriorated due to his illness. Over the decades, he became paralyzed throughout his entire body, save for a muscle in his cheek, which was attached to a speech-generating device that allowed him to communicate.

In 1988, Hawking penned A Brief History of Time, which explained a number of scientific theories about the nature of the universe in accessible layman's terms which made the material understandable to those without prior knowledge of study of the topics the book explained. 

The book became an international hit, selling over 10 million copies in 20 years and was translated into more than 35 languages. The book remained on the British Sunday Times best-seller list for a record 237 weeks, and it cemented Hawking's place in the public consciousness as a celebrity in the world of theoretical physics.

Hawking -- who received the Presidential Medal of Freedom in 2009 – was an advocate of the many-worlds interpretation of quantum mechanics and came up with a theory about radiation emitted by black holes, which became known as Hawking Radiation.

The acclaimed scientist was the subject of the 2014 biographical drama The Theory of Everything, in which he was played by Eddie Redmayne, who won an Oscar for his performance.

During a press junket for the film, ET spoke with Redmayne and co-star Felicity Jones – who played Jane Hawking, his first wife and the mother of his three children – and the actor opened up about what it was like meeting the legendary scientist to do research for the role.

"I spent four months preparing to play him and then when I met him I got basically verbal diarrhea and spent half an hour telling him about himself," Redmayne recalled. "It got so bad that I was filling the air and I was reminding him that he was born on the 8th of January which is Galileo's birthday. I then said, 'I was actually born on the 6th of January, and so we're both Capricorns.' And the word Capricorn came out of my mouth and I don't think I've ever felt so horrific in my life."

"He spent like 10 minutes typing something out and then said, 'I'm an astronomer, not an astrologer,' Redmayne recalled, laughing.

ET has reached out to a rep for Hawking.

For more on Hawking's life and legacy, and his reaction to seeing his life portrayed on the big screen, check out the video below.