British Prime Minister Keir Starmer apologized to a headteacher on Monday after accidentally leading a chorus of the viral "6-7" chant while visiting a primary school class in Peterborough.

Footage posted to Starmer's Instagram showed the Prime Minister reading with a young girl when she pointed out the page numbers six and seven in the book before saying "6-7" and performing the accompanying viral juggling hands gesture.

Starmer immediately imitated her and other pupils needed little encouragement to join in.

"That was a bit wild," Starmer said to Welland Academy headteacher Jo Anderson as he left the class.

"Thanks, Prime Minister for that lovely 6-7. You know children get into trouble for saying that in our school?" Anderson replied.

As they walked down the hall a few moments later, the fact that he'd unwittingly encouraged a banned "6-7" session was clearly playing on the Prime Minister's mind.

"Sorry about that," he told Anderson.

"No, no, it's absolutely fine" she responded.

"I didn't start it, Miss," Starmer joked.

“6-7” is a viral term that kids and teenagers can’t stop repeating and laughing about and parents and teachers can’t make any sense of.

It exploded in popularity over the summer and appears to be an inside joke with an unclear meaning, driven by social media.

Dictionary.com which made "6-7" it's word of the year said it's a linguistic time capsule reflecting social trends and events. But the site admitted it too is a bit confused by “6-7.”

It all seems to trace back to rapper Skrilla’s song from 2024 called “Doot Doot (6-7).”

That song started appearing in TikTok videos with basketball players, including the NBA’s LaMelo Ball who stands 6-foot-7.

Then a boy, now known as “The 6-7 Kid,” shouted the ubiquitous phrase while another kid next to him juggled his hands in a video that went viral this year.