Britain's Got Talent finalist Viggo Venn swore during the live grand final.
The Norwegian comedian - who was voted the winner of the 16th series of the ITV talent show - used the expletive during his act as he pretended something had gone wrong.
Ant McPartlin said afterwards: "We must apologise for any bad language that you might have heard during that. Not naming names. Somebody did."
Venn gave head judge Simon Cowell a giant pin before running off stage and coming back holding a giant red balloon. But he lost hold of the balloon and it blew away into the audience.
Venn could be heard saying "Oh s**t!", before asking hosts Ant McPartlin and Declan Donnelly "Is this live?"
But it was all part of the act as he went and retrieved another giant green balloon which he returned to the stage wearing on his head. A warning "Do not try this at home" appeared on screen in giant letters.
Venn climbed inside the balloon before asking Cowell to save him by popping it.
His segment aired on the ITV show just after the 9pm watershed.
The Britain's Got Talent 2023 final featured 11 acts competing to win a cash prize of £250,000 and a chance to perform at King Charles III's very first Royal Variety Performance as reigning monarch.
It is not the first time BGT hosts Ant and Dec have had to apologise for bad language in the latest series.
Gasping that he could not watch, he said "F**king hell Simon, not again! Not again..."
During the live broadcast hosts Ant and Dec were not aware the expletive had been picked up by mics and heard by viewers at home. But on the next semi-final they apologised for Tonioli's language.
The new judge then swore again when he was called up on stage to take part in magician Miki Dark's guillotine stunt.
Watch: Alesha Dixon says Bruno Tonioli does not know the rules of Britain's Got Talent