Fox News host Pete Hegseth has said on air that he has not washed his hands for 10 years because "germs are not a real thing".
Speaking on Fox and Friends, Hegseth said the infectious micro-organisms did not exist because they could not be seen with the naked eye.
"I inoculate myself," added the Harvard and Princeton graduate.
His remarks came after co-hosts Ed Henry and Jedediah Bila made fun of him for eating left-over pizza.
"My 2019 resolution is to say things on air that I say off air," Hegseth added.
His comments were met with both support and concern on social media.
@PeteHegseth I'm with you on hand washing. I'm almost 70 and haven't had a cold or flu in years. Our bodies need some germs to learn how to fight them. Too many germofobes out there.— Smittymhs (@smittymhs) February 10, 2019
I wonder if @PeteHegseth would be cool with restaurant workers preparing his food after deliberately not washing their hands?— Bradley P. Moss (@BradMossEsq) February 10, 2019
Mr Hegseth later told USA Today that his remarks were intended to be a joke.
"We live in a society where people walk around with bottles of Purell (a hand sanitiser) in their pockets, and they sanitise 19,000 times a day as if that's going to save their life," he said.
"I take care of myself and all that, but I don't obsess over everything all the time."
Of the public reaction, he said it was ridiculous how people took things so "literally and seriously" so that their "heads explode".
The US-based Centers for Disease Control and Prevention says regular hand washing "is one of the best ways to remove germs, avoid getting sick, and prevent the spread of germs to others".
According to a scientific study published by the US National Center for Biotechnology Information, one gram (0.03oz) of human faeces - about the weight of a paper clip - can contain one trillion germs.
Bacteria that can be spread by unwashed hands include salmonella and E coli.
US President Donald Trump - who has given more interviews to Fox than any other major network - has admitted on several occasions to being a germophobe.
In his 1997 book, The Art of the Comeback, Mr Trump wrote: "One of the curses of American society is the simple act of shaking hands, and the more successful and famous one becomes the worse this terrible custom seems to get.
"I happen to be a clean hands freak. I feel much better after I thoroughly wash my hands, which I do as much as possible."
One BBC reader, Steve M, said: "I didn't think I would ever say this - I agree with Donald Trump on this!"
"It would seem that attending Harvard and Princeton might provide knowledge, but obviously not any sense."
Some noted that being too obsessed with hygiene could also be a bad thing, by possibly lowering one's natural resistance to germs.
But, as reader Kevin Cook put it: "Not washing your hands at all for 10 years strikes me as reckless disregard for other people's health."