Queensland media personality Billy J Smith has died aged 73.

The radio star, football commentator and host of '80s game show It's a Knockout was placed on life support after a fall on Caxton Street where he had enjoyed lunch with friends yesterday.

He died in hospital today after his family made the decision to turn off his life support.

Billy J Smith in an episode of game show It's a Knockout. (Supplied)

Former colleague and radio personality Donna Lynch said Smith could be for his trademark insults and acid tongue but those who knew him knew he had a "heart as big as Queensland".

"I can't imagine Brisbane without Billy," she said.

"You knew every time you went out anywhere with Billy that you were going to have a laugh and really at the end of the day that’s the best thing in life isn't it."

Smith called the very first State of Origin rugby league clash when Suncorp Stadium was still called Lang Park and was involved in the first version of The Footy Show in Queensland.

Billy J Smith on an early version of The Footy Show. (Nine)

Rugby league legend Wally Lewis described Smith as the "ultimate entertainer of his time".

"I'm sure Billy's family are certainly feeling it more than anybody else," Lewis said.