But while some called the kid a “legend for life” for following British tradition,” others wondered if he’d found shame not fame.
The lad sneaked in his gesture when he noticed cameras focusing on commentators in front of him at London’s O2 Arena.
He was obscene and not heard – as it was purely a visual moment.
But not all viewers condoned his antics on a night when for the first time the show was televised live and in primetime across the pond.
On the one hand, the boy’s moment of gladness might have been spontaneous.
But on the other hand, he seemed far from bashful afterwards, settling back in his seat with a huge grin.
Some viewers gave a thumbs-up to his action – which was not too unlike the lad’s gesture.
Such verdicts included: “Makes me proud to be British” and “That kid following proper British tradition”.
His action was also called “brilliant” – while some called him a “legend” and one enthused: “Love it!”.
But a few posted their disapproval.
“Typical,” said one, while there were also crying emojis.
In contrast, the event opened far more classily.
There was a tribute to Darren Drozdov, the former WWE star and ex-gridiron player, who died on Friday aged just 54.