Newsreader Fredrik Ahl sang opera and spoke in funny voices during a taped test run by Swedish public broadcaster SVT's regional Sörmland's news programme on Wednesday night.
But the 43-year-old was unaware that his impromptu performance was being broadcast to a number of viewers watching the channel via its digital network.
One of them was was Marcus Hagsten, 21, in Huddinge just south of Stockholm, who quickly recorded the highly unusual local news report on his camera phone.
“My parents came and got me and said 'you have to come and watch this, it's completely insane,” he told Swedish newspaper Metro on Thursday.
“[The news reader] then started to sing and freaked out completely. It was so weird,” said Hagsten and added the unconventional broadcast went on for about an hour.
During that time, Ahl read a news report about the jobs market in the Swedish town of Eskilstuna, adding 'noboby wants to live in Eskilstuna' and feigned removing ear wax from his ear phone.
But what caused the biggest stir in Sweden was his parody of a recent news report about asylum seekers and the Swedish jobs market saying “those who come are often educated engineers, doctors and kebab technicians”.
“If anybody has been offended I flat out apologize. You should choose your words. If I had known it was going to be aired, I would not have said it,” a regretful Ahl told the Expressen tabloid on Thursday.
“I know that I often joke around before a television broadcast to help me get started. I am a bit of a clown and I use playful jargon,” he said.
Hans Zetterberg, head of SVT Sörmland, told Expressen that despite a thorough technical investigation the broadcaster had not been able to work out how or why the clip ended up on air.
He added that Ahl is normally one of the network's best newsreaders.
“But what he says towards the end is rude, and I have spoken to Fredrik. We can only apologize,” said Zetterberg.
The incident took place less than a week after SVT was forced to apologize to parents for accidentally sending a text message with a link to gay porn to 60 school children.