Have you ever held in a fart to save face? Chances are, if you're honest, the answer to that question is a yes.

But, what you're about to read might make you think twice next time you feel that build up of gas in your tummy.

Because holding a fart in won't just leave you feeling uncomfortable — it could end up in you breathing the fart out your mouth instead.

That's according to Professor Clare Collins, a nutrition and dietetics expert at the University of Newcastle.

Writing for The Conversation, she said holding in trapped wind could cause abdominal distension, "with some gas reabsorbed into the circulation and exhaled in your breath".

"Holding on too long means the build-up of intestinal gas will eventually escape via an uncontrollable fart," Prof Collins added.

Meanwhile, she warned it could also lead to a condition called diverticulitis but pointed out the evidence wasn't clear.