Nicholas Parsons missed a recording of his Just A Minute radio show for the second time in more than 50 years due to a back problem.
The veteran broadcaster, 95, was replaced by Gyles Brandreth for the recording of two episodes of the BBC Radio 4 comedy programme at the Edinburgh Festival Fringe.
A BBC spokeswoman said: “Unfortunately, Nicholas Parsons has got a bad back, so Gyles Brandreth hosted a couple of episodes of Just A Minute which were recorded yesterday.
“We expect to see him back in the chair for the next recording.”
The episodes are due to air later this month.
Parsons has fronted the programme, where panellists have to speak for one minute without hesitation, deviation or repetition, since its inception in 1967.
He only missed an episode for the first time last year due to a bout of flu.
Parsons later told BBC Radio 4’s Today programme that the BBC was “ridiculous” for originally saying he had taken a couple of days off after listeners had been concerned about his unlikely absence.
“In our profession you don’t take days off,” he told the programme.
“You are terrified someone is going to take the job from you.”
Brandreth, a regular contestant on the programme, filled in for Parsons during his absence at the time.
Parsons is due to start a four-night run of his comedy show at the Edinburgh Fringe on Thursday.