Jamie Laing warned fans to check their carbon monoxide alarms after he discovers his whole apartment building is full of the deadly gas.
The Made In Chelsea star, 33, said that he was woken up at 6am by the alarm beeping, but that he was grateful for it as it "could have been a very different story."
On a Instagram story, he told his 980k fans: "Guys it's 6am and my carbon monoxide alarm is beeping, so I googled it and they told me to call the Gas Emergency, never had to phone them before, and I was also told to open a window."
He then pointed at the ceiling and said: "You hear that? It's carbon monoxide".
The reality star then asked his followers for advice on whether he should stay inside or leave the building.
"So, if anyone has had a carbon monoxide alarm buzzing or ringing, let me know what to do. Do I sit inside? Do I not sit inside? How dangerous is it? Any tricks to sleep as well because I'm absolutely exhausted, it's been going on for half an hour."
Two hours later Jamie returned with some scary news after he had a professional come in to assess the situation.
Captioning the video "serious talk", Jamie said: "Little update, the Gas emergency guy has just come over, Steve, nice guy.
"He told me the whole building is full of carbon monoxide, silent killer. Can't taste it, feel it, sense it, nothing at all.
"The whole building is full of carbon monoxide, full of it. Everyone's fine, everyone's all good, it's clear now," he assured.
"But my point is, if it wasn't for that beeping alarm, it could have been a different story, who knows," he added.
"So if you haven't checked your carbon monoxide alarm, if you haven't checked it, tested it, if you haven't got one -check it.
"Test it this weekend because it's a silent killer, so there you go - check it, everyone is ok and yeah," he finished.
Carbon monoxide can be extremely dangerous when breathed in as it displaces the oxygen and deprives organs of air.
Large amounts can cause damage to the body within hours or even minutes, potentially causing loss of consciousness, suffocation, and death.
His fiancee Sophie Habboo didn't appear to be in their two-bed Chelsea pad flat during the ordeal.
The couple, who are set to get married in May next year, turned down offers for their wedding to be filmed as part of a Made In Chelsea special.
Jamie also quit the series to focus on their relationship, after arguing that he's "seen so many relationships fail on reality TV".