Famed Johnny Carson sidekick Ed McMahon, seen here in 2007, died early Tuesday. (Matt Sayles/Associated Press)

Ed McMahon, former sidekick to Johnny Carson on NBC Television's Tonight Show, has died at age 86 in Los Angeles.

McMahon died early Tuesday morning at the UCLA Ronald Reagan Medical Center, according to his publicist, Howard Bragman.

He didn't release a cause of death, saying only that McMahon had a "multitude of health problems the last few months."

The famed funnyman had been hospitalized with pneumonia and other ailments earlier this year, and had reportedly battled bone cancer.

"Ed McMahon's voice at 11:30 was a signal that something great was about to happen. Ed's introduction of Johnny was a classic broadcasting ritual — reassuring and exciting," late-night TV host David Letterman said in a tribute, adding, "We will miss him."

Doc Severinsen, who served as the bandleader on Tonight during Carson's years, hailed McMahon as a man "full of life and joy and celebration" and said he would be missed.

"He was one of the greats in show business, but most of all he was a gentleman. I miss my friend," Severinsen said in a statement.

Born in Detroit in 1923, McMahon began his career as a bingo caller in Maine at age 15, and he put himself through college as a pitchman for vegetable slicers on the Atlantic City boardwalk.

During the Second World War, he trained as a U.S. marines fighter pilot, and served as a flight instructor and test pilot. He was discharged in 1946.

McMahon graduated from the Catholic University of America in Washington, D.C., in 1949, majoring in speech and drama. After graduation, he returned to active duty with the marines and was sent to Korea in 1953.

McMahon got his first broadcasting job at WLLH-AM in Lowell, Mass., and began his television career at WCAU-TV in Philadelphia.

His major break came in the late 1950s, when ABC decided to replace ventriloquist Edgar Bergen and his puppet sidekick, Charlie McCarthy, on the daytime game show Who Do You Trust? Carson was brought in as the host, and McMahon got the "dummy's" role.

'Ed McMahon's voice at 11:30 was a signal that something great was about to happen. Ed's introduction of Johnny was a classic broadcasting ritual — reassuring and exciting ... We will miss him.'—David Letterman

When Carson took over the Tonight Show from Jack Paar in 1962, he took McMahon with him. For 30 years, McMahon introduced Carson with a resounding "Heeeeere's Johnny!" and bolstered him with hearty laughs. When Carson retired in 1992, McMahon left the show, too.

"You can't imagine hooking up with a guy like Carson," McMahon told The Associated Press in a 1993 interview. "There's the old phrase, hook your wagon to a star. I hitched my wagon to a great star.

"It's like a pitcher who has a favourite catcher," he added. "The pitcher gets a little help from the catcher, but the pitcher's got to throw the ball. Well, Johnny Carson had to throw the ball, but I could give him a little help."

McMahon also had supporting roles in movies including Fun with Dick and Jane (1977), Just Write (1997), Butterfly (1982) and in the film version of Bewitched (2005). He co-hosted Jerry Lewis's muscular dystrophy telethons, and appeared in numerous television commercials, most notably for Budweiser.

Plagued by ill health

McMahon's recent years had been plagued by ill health and financial woes.

In 2002, he sued his insurance company for more than $20 million US, alleging he and his wife Pamela had become ill from toxic mould in his home after contractors cleaned up water damage from a broken pipe. He eventually won $7 million US when it was determined that several contractors had been negligent in allowing mould to grow in his home.

In 2007, he broke his neck in a fall. Last year, he faced foreclosure on his Beverly Hills home when he fell behind on payments on $4.8 million U.S. in mortgage loans. He said the neck injury had left him unable to work, but a deal was announced in December that allowed him to remain in the house.

McMahon is survived by this third wife, Pamela, whom he married in 1992, and three daughters and three sons.

Bragman said funeral arrangements have not yet been made.

With files from The Associated Press