American crooner Andy Williams, whose string of hits like "Moon River" and annual Christmas TV shows made him a national treasure, has died aged 84 after losing his battle with cancer.

Wildly popular in the 1960's, with 18 gold and three platinum records to his name, the clean-cut master of easy listening and the sentimental soundtrack signed what was at the time the biggest US recording contract.

"Legendary singer Andy Williams passed away last night (Tuesday) at home in Branson, Missouri following a year long battle with bladder cancer, it was announced by his family," his publicist said in a statement.

Born in Wall Lake, Iowa, a son of a railroad worker, Howard Andrew Williams sang in his family's church choir with bothers Bob, Dick and Don -- a precursor for what was to become a 75-year professional singing career.

After World War II, they joined entertainer Kay Thompson in her innovative and sophisticated nightclub act. In his 2009 memoir "Moon River and Me," Williams admitted a long affair with Thompson, 18 years his senior, as she coached him professionally.

On his way to earning more gold albums than any other solo performer bar Frank Sinatra, Johnny Mathis and Elvis Presley, Williams won an Oscar for his rendition of "Moon River" in the 1961 hit film "Breakfast at Tiffanys."

That led to NBC's signing of Williams for his popular "Andy Williams Show" in 1962, which was on the air for almost a decade, until 1971.

A frequent host of the Grammys and Golden Globes, Williams was also known for his television Christmas specials and in later years, decked out in his trademark red cardigan, he became an annual fixture in American homes.

Williams was survived by his wife Debbie, and his three children Robert, Noelle and Christian, with French-born dancer Claudine Longet.

He and Longet divorced in 1975 and the following year she was charged with fatally shooting her ski racer boyfriend Spider Sabich in Aspen. Williams stood by her side throughout the trial. He wed Debbie Meyer in 1991.

Williams' birthplace in Iowa is a tourist attraction and in the 1990s opened a theater in his adopted hometown of Branson, Missouri -- it is called Moon River Theater after the song he made so famous.

"In lieu of flowers, the family asks that donations be made to the Bladder Cancer Advocacy Network," publicist Paul Shefrin said in a statement.