Perry Como, the crooning baritone barber, famous for his relaxed vocals, cardigans and television Christmas specials, has died after a lengthy illness. He was 87.

Como died in his sleep at his home in Jupiter Inlet Beach Colony, his daughter Terry Thibadeau said.

"We spent two beautiful hours (Friday) with dad, me and my grandson, Holden," Thibadeau told The Palm Beach Post.

"We shared ice cream. It was a wonderful moment for us."

The charming Italian-American whose name became synonymous with mellow performed through seven decades, starting in the 1930s.

His idol, the late singer Bing Crosby, once called Como "the man who invented casual".

Como left his job as a steel town barber to sing with big bands in the 1930s and his songs were a mainstay of radio and jukeboxes in the late 1940s.

He helped pioneer variety shows on the new medium of television in the 1950s and performed on television specials over the last four decades.

His music remained popular in recent years on easy-listening radio.

In 1945, Como had his first million-selling hit, Till the End of Time.

It was among many songs including Prisoner of Love that topped the charts.

He competed with Frank Sinatra and Crosby to be the era's top crooner.

While Como emulated Crosby in his early years, some of his best-known numbers were light novelty songs like Hot Diggity and Papa Loves Mambo.

He made a brief foray into wartime movie musicals in Hollywood, but decided to pursue a career in radio.

Como often said he far preferred singing romantic ballads to some of the lightweight numbers, but the novelty songs were a frequent audience request.

"They get tired of hearing Melancholy Baby and those mushy things," Como said in a 1994 interview.

"But those are the songs that, as a singer, you love to sing."

Some music experts say Como, with his naturally melodic baritone voice, might have carved a deeper niche if he had taken firmer control of his material.

Will Friedwald, author of Jazz Singing and an expert of music from Como's era, once called Como "a marvelous singer" who "seemed to do everything they put in front of him".

Como made his television debut in 1948 on NBC's The Chesterfield Supper Club and in 1950 he switched to CBS for The Perry Como Show, which ran for five years.

Como then returned to NBC for a variety show that ran for eight years, first on Saturday nights opposite Jackie Gleason, then on Tuesday night.

In 1963, he gave up the regular television show and began doing occasional specials.

Rock 'n' roll had crowded out the crooners who once charmed hordes of screaming bobby-soxers.

His career saw a resurgence in the 1970s with songs like It's Impossible, And I Love You So and several best-selling Christmas albums.

In 1994, Como put out a three-CD boxed set including his most popular songs since he started recording in 1943.

And his former hit, Catch a Falling Star, became familiar to a new generation of fans when it became part of the Clint Eastwood-Kevin Costner movie A Perfect World.

Como said he occasionally tired of the jokes about his somnambulant style, although he found a skit on the SCTV comedy show particularly amusing.

The spot showed a Como impersonator lying on the floor nearly comatose with a microphone in front of his barely moving lips as dancers leaped about him.

His casual legend grew from his first pressure-packed appearances on the pioneering medium of live television - with its crashing scenery, misplaced cue cards and camera confusion.

"I decided the only thing to do was take it as it came," he recalled in a 1985 interview.

"People wrote in asking how I could be so casual. It all started to grow."

Pierino Roland Como was born May 18, 1913, in Canonsburg, Pennsylvania, the middle offspring of 13 children of Italian immigrants.

At age 11, he went to work sweeping floors after school at a barber shop in the town just south of Pittsburgh.

He got lessons on how to cut the hair of coal miners and other workers, and by the age of 14 he had his own barber business earning $US150 ($A287) a week. His pay dropped off during the Depression when he went to work for another barber.

But he got an offer to sing with Freddie Carlone's band in Cleveland in the early 1930s.

He began his rise in show business when he was signed to sing with Ted Weems big band in 1936, a relationship that continued for six years.

In 1943, he began what turned into a 50-year contract with RCA-Victor Records with the recording of the song Goodbye Sue.

In his later years, Como lived in a private semiretirement with his wife Roselle, whom he met at a picnic when he was 16 and married in 1933.

They divided their time between the North Carolina mountains and the Palm Beach County town of Jupiter where he played golf, took long, brisk walks and entertained his grandchildren and great-grandchildren.

Mrs Como died in August 1998, less than two weeks after she and Como celebrated their 65th wedding anniversary. She was 84.

He reappeared on television periodically for Christmas television specials from exotic, international locales.