Jeremy Corbyn failed to recognise two of the UK's most popular TV presenters - Ant and Dec - in a general knowledge quiz.
The Labour leader also stumbled over how many Olympic gold medals cyclist Bradley Wiggins has won, despite tweeting his congratulations to the athlete just days ago.
Jeremy and his rival Owen Smith were tested on their pop culture knowledge during a live debate on BBC One.
The embattled party leader failed to identify Britain's Got Talent hosts and Labour supporters Anthony McPartlin and Declan Donnelly when he was shown a photo of the pair.
Despite being told they were Geordie TV presenters, he told the BBC's Victoria Derbyshire: "I cannot name them, I'm really sorry."
After being told who they were, he added: "I hope they'll be happy about this. They sent an email of support.
-- Victoria Derbyshire (@VictoriaLIVE) August 17, 2016
"I will apologise humbly for my mistake. I do apologise, it's alright."
Owen, however, was quick to name pop stars Taylor Swift and Justin Bieber when shown an image of the two at an awards ceremony.
Twitter users following the debate were in two minds over Jeremy's lack of pop culture knowledge, especially considering Ant and Dec's long-running fame in the UK.
Some joked that Labour supporters would turn on him now, while others commented that they preferred their leader to not be aware of such things.
I don't think the British people will accept a man as Prime Minister who doesn't know who Ant and Dec are. This just got serious. #Corbyn
-- Mark Somers (@MarkSomers) August 17, 2016
-- keith walton (@keithwalton1) August 17, 2016
-- RobinMarsden (@lets_go_real) August 17, 2016
#CORBYN Just gone up in my estimation .Didnt recognise Ant and Dec
-- MrMoose (@MrMoosesTaxi) August 17, 2016
I think I'd vote for a Prime Minister who had no idea who Dec and Ant were.... #Corbyn
-- Dominic McGladdery (@dominic_mcg) August 17, 2016
-- James Moulding (@Jamo133) August 17, 2016
-- Maeve Begley (@MaeveBeg) August 17, 2016
-- MissM (@MissMcN) August 17, 2016