Ed McMahon, shown in July 2007, is in serious condition in a Los Angeles hospital. (Matt Sayles/Associated Press)

Ed McMahon, the American comedian who played sidekick to Johnny Carson on The Tonight Show for 30 years, is in intensive care in a Los Angeles hospital, a spokesman said Friday.

McMahon, 85, has been in hospital for several weeks, suffering from pneumonia and other ailments, spokesman Howard Bragman said.

Bragman said McMahon is in serious condition and his wife and family are with him.

"We're hopeful," he added.

McMahon broke his neck in a fall in 2007 and has recently been in the news because of his financial problems.

He faced foreclosure on his $4.5 million US home last year and was sued by banks and lending agencies.

However, in December, Donald Trump stepped in to buy the mansion and said he would allow McMahon to continue living there.

Fought in Korean War

McMahon had been working as a pitchman for Neighbourhood Watch and American Family Publishing, but said he got into difficulty because he had not been able to work while recovering from his injuries.

Born in Detroit, McMahon fought in the Korean War and moved into broadcasting after he finished his military service.

He worked in game shows in the 1960s, starting out in Philadelphia.

He and Carson first worked as host and announcer of daytime game show Who Do You Trust? from 1957 to 1962. He moved with Carson to The Tonight Show in 1962.

McMahon was known for his hearty laugh and his booming voice, especially in the "H-e-e-e-re's Johnny!" at the beginning of every show. Carson died in 2005.

After leaving the show in 1992, McMahon was host of talent show Star Search and appeared on TV in Baywatch, The Tom Show and as the voice of Tugboat Captain Hero on Higglytown Heroes.

With files from the Associated Press