David Cameron suggested that Jeremy Corbyn "go back to 1985 and stay there" as the world celebrated Back to the Future Day.
Back to the Future Day, which marks the day Marty McFly and Doc Brown arrive in the future in the 1989 sci-fi film Back to the Future II, has been the subject of choice for politicians trying hard to be cool on social media this Wednesday.
London mayor candidate Sadiq Khan went as far as to pledge "freezing fares for flying cars".
But Cameron took it one step further, responding to a question in parliament on the renewal of the UK's nuclear weapons by making a topical jibe at Labour leader Jeremy Corbyn, saying Corbyn's alignment with the Campaign for Nuclear Disarmament belongs in the 1980s.
Cameron joked: "It's today that we're celebrating that great film Back to the Future and I'm not surprised that many people sitting behind him say he should get into his DeLorean and go back to 1985 and stay there."
It's fair to say the joke hasn't had an overwhelmingly positive reaction.
Yep, nothing at all tortuous about Cameron's shoe horned reference to Back to the Future in Prime Minister's Questions.
In fact people don't seem to be very happy at all.
DAVID CAMERON JUST MADE A BACK TO THE FUTURE JOKE AND I AM EXTREMELY ANGRY ABOUT THIS
People think the prime minister has ruined the joyous day of celebration.
EVEN CAMERON MADE A BACK TO THE FUTURE JOKE CAN'T YOU PEOPLE SEE WHAT YOU'RE DOING
"You're not cool enough to do that. Sit down."
David Cameron just made a #BackToTheFuture reference in the House of Commons... No David, you're not cool enough to do that... Sit down
In fairness to the prime minister, not everyone hated it.
I actually thought Cameron's Back to the Future joke was quite good. #PMQs
But most people really, truly did.
David Cameron mentioned Back to the Future day. We'll that's that ruined