Nothing to see here, carry on folks.
Amid the bewilderment, the bold entrance drew praise from Sweden’s Ambassador to the UK.
It’s not yet known what the songwriter of the ABBA classic - the passionately anti-Brexit Björn Ulvaeus - thinks about it but HuffPost UK has contacted his agent for comment.
As if all this wasn’t jarring enough, the famously-robotic Theresa May cracked an actual joke.
And then went straight into ANOTHER JOKE, both referencing this time last year when a tickly cough and a shabby set ruined her 2017 speech.
She said: “You’ll have to excuse me if I cough during this speech. I’ve been up all night supergluing the backdrop.”
The dancing was of course a reference to May’s widely-mocked attempt to dance on a number of occasions when on a tour of Africa earlier this year.
But the jolly tone of the speech didn’t last long as she paid tribute to those who died in the First World War, which ended 100 years ago.
She also highlighted the efforts to rebuild in the wake of the Second World War “where former enemies become friends”.
She said: “We must recapture that spirit of common purpose because the lesson of that remarkable generation is clear: if we come together there is no limit to what we can achieve.
“Our future is in our hands.”
Our... jazz hands?