Alex Trebek, whose decades as host of the quiz show "Jeopardy!" made him one of the most popular fixtures on American television, died on Sunday at age 80.

Trebek had waged a very public fight against pancreatic cancer for nearly two years, but continued taping his program until recently.

His death was announced on Twitter by the "Jeopardy!" account, which said Trebek "passed away peacefully at home early this morning, surrounded by family and friends," adding: "Thank you, Alex."

CNN media analyst Brian Stelter called Trebek "the greatest game show host of his generation... You always watched, and you came away smarter."

Even Canadian Prime Minister Justin Trudeau tweeted his condolences for the family of the Canadian-born Trebek.

"We have lost an icon," he said. "Almost every night for more than three decades, Alex Trebek entertained and educated millions around the world, instilling in so many of us a love for trivia."

Trebek, who became a US citizen in 1998, had hosted "Jeopardy!" -- syndicated these days to various channels including ABC -- since 1984.

Bob Iger, the executive of ABC parent the Walt Disney Company, called Trebek "a friend, a colleague, an icon" in a statement mourning his death.

- A 36-year run -

Trebek previously hosted other game shows, including "Double Dare" and "Classic Concentration," as well as hosting the National Geographic Bee for 25 years.

But it was his time at "Jeopardy!" -- a 36-year run almost unheard of by television standards -- and his clear intelligence, gentlemanly aplomb and sly good humor that earned him the eternal devotion of millions of viewers.

He also won a slew of awards. Trebek was a five-time daytime Emmy Award winner. He had a star on the Hollywood Walk of Fame.

He was so deeply immersed in American popular culture that Trebek -- or his imitators -- appeared in numerous movies and TV shows; comedian Will Ferrell played him on "Saturday Night Live"; he once even drew headlines by shaving his signature moustache.

Sometimes two or even three generations of viewers would gather before televisions to watch him.

One contestant, Burt Thakur, grew tearful on a recently aired episode when he told Trebek how, as a small child in India, he watched the show on his grandfather's lap. 

"I realized English due to you. And so, my grandfather who raised me ― I'm going to get tears proper now ― I used to take a seat on his lap and watch you day by day."

- Cancer diagnosis -

Trebek received a flood of supportive mail after announcing his Stage 4 cancer. "I'm going to fight this," he told his fans. Many wrote to tell him they were inspired by his battle.

He had had earlier health scares, including two heart attacks and a bad auto accident, but always came back. 

George Alexander Trebek was born on July 22, 1940, in Sudbury, Ontario, Canada. His father was a Ukrainian immigrant; his mother a French-speaking Canadian.

With a degree in philosophy in hand, he went to work for the Canadian Broadcasting Corporation in 1961; by 1966 he was hosting a high school quiz show.  

Trebek moved to the United States in 1973 to host a new NBC game show, "The Wizard of Odds."

He took over the reins at "Jeopardy!" in 1984 when a friend of his, original host Art Fleming, declined to return.

Trebek held the record for the most game show episodes hosted by the same presenter, at 6,829, according to Variety.

"You work hard, you do your best," he said with typical modesty at one awards show.

He and his wife Jean Currivan have two children.