The 30-year-old presenter, who is no stranger to breaking down in fits of giggles on the morning programme, was helping out chef Gino D'Acampo in the kitchen when she made the mistake.
Referring to the cheese the pair were cooking their pork with, Holly called it 'pecorina' instead of pecorino cheese.
However, Holly, who was also being aided by co-presenter Phillip Schofield, 49, was entirely unaware that in Italian, pecorina actually means a certain kind of sexual position.
Red faced: Holly Willoughby was left embarrassed after mispronouncing a cheese on This Morning, accidentally referring to a sexual position instead
Shocked D'Acampo hastily corrected her pronunciation but managed to gloss over the faux pas by telling her pecorina meant something different in Italian.
Gino, who was also being aided by co-presenter Phillip Schofield, 49, managed to gloss over the faux pas.
A source said: 'Holly innocently referred to pecorino as pecorina which has an entirely different meaning in Italian. It refers to having sex doggy style.
Domestic goddess: Holly was cooking with Gino D'Acampo when she made the error
Whoops! Gino managed to keep a straight face after Holly's faux pas
'Gino corrected Holly on air but didn't tell her what the error referred to. He did well to keep a straight face.'
Soon after Holly's mistake, This Morning guest presenter Jenni Falconer took to Twitter to poke fun at the mispronunciation.