The presenter, 94, has been on the BBC Radio 4 panel game since its inception in December 1967, but missed last night’s instalment.
Gyles Brandreth filled in for him – prompting an outpouring of worried messages on social media from Parsons’ fans.
BBC head of radio comedy Julia McKenzie was quick to assure listeners that Parsons was just enjoying a rare “couple of days off”.
She tweeted: “Just to reassure those listening to the very unexpected Just A Minute on BBC Radio 4 at the moment – the apocalypse is not upon us – Gyles kindly stepped in to give Nicholas Parsons a couple of days off.
“NP is totally fine and is still the guv’nor as per the last 50 years.” However, plenty of people still posted messages online saying that Just A Minute without Parsons felt like the end of the world.
One said: “The latest sign of the impending apocalypse. Nicholas Parsons is not in the chair for Just A Minute.”
Another fan said: “OMG what is happening. Nicholas Parsons isn’t presenting Just A Minute. End of days. BBC Radio 4.”
Another said: “Somewhere, the captain of a nuclear submarine is trying to work out what it means when Nicholas Parsons isn’t hosting Just A Minute.”
And one person suggested it was like “the ravens leaving the Tower of London”.
Ms McKenzie responded to some of the comments, assuring the concerned fans: “He’s totally fine – we thought we’d allow him a day off after 50 years.”
She replied to another message by saying: “Yes don’t worry he is fine and well – just a day off.”
Another tweet read: “NP is totally fine. Just taken a couple of days off – he has a 50-year perfect attendance record so we thought that was probably OK.”