A Fox News host told viewers that he has not washed his hands in 10 years because "germs are not a real thing".
Appearing on the channel's breakfast show Fox and Friends on Sunday, Pete Hegseth claimed that germs do not exist as he "can't see them".
The presenter added that he has made himself immune to disease and bacteria by not washing his hands.
The admission was prompted by his co-host Jedediah Bila pointing out that he had eaten leftover day-old pizza in the studio.
During the programme, Mr Hegseth said his New Year's resolution was to “say things on-air that I say off-air” before explaining his personal hygiene routine.
He said: "I don't think I've washed my hands for 10 years.
"Really, I inoculate myself. Germs are not a real thing. I can't see them therefore they are not real."
Laughing at his admission, Ms Bila said: "So you're becoming immune to all of the bacteria?"
Mr Hegseth replied: "Exactly. I can't get sick."
He doubled down on his claim immediately after the show, retweeting a message of support with the hashtag #DontWash.
But in a further tweet on Monday he appeared to suggest he had been joking.
Presenter Chris Hayes wrote: "He's... pretty clearly joking."
Mr Hegseth replied: "When even @chrislhayes can see the obvious...Twitter really has come full circle."
The US-based Centers for Disease Control and Prevention states regular hand washing "is one of the most important steps we can take to avoid getting sick and spreading germs to others".
