The 73-year-old host could be seen getting red-faced as he realised he’d made a bit of an error.
During the words game, the letters R, L, D, A, O, U, E, F and R came up on the board.
Contestant Pete Grange offered “folder”, while rival James Slater came up with the word “floured” which won him the round.
“Floured is absolutely fine. You can flour a worktop, for example. I’m pretty sure it’s a verb,” Susie Dent in Dictionary Corner told him.
She added: “Yes, to sprinkle a work surface with flour.”
However, Nick was clearly not paying attention to the game and said casually: “Or a dress? Flour dress?”
Nick Hewer was left shocked after a gaffe on Countdown
Countdown host Nick Hewer was left red-faced
I never look at the board!
When members of the audience started laughing, the former Apprentice star realised his mistake and exclaimed: “Oh, I’m sorry!”
He covered his mouth in horror and then his face in embarrassment, before explaining himself: “I don’t – I never look at the board!”
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“I’m so sorry! I was thinking it’s obviously a flowered dress. I really must pay more attention to the letters being put out!” he said.
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This is the hilarious moment Countdown brainbox Rachel Riley was forced to spell out the word BUMHOLE
Nick Hewer revealed he didn't read the board properly
Even brain box Rachel Riley was struggling not to laugh at the hilarious moment.
“There we go, a floured work surface of course,” Nick added as he tried to move things on, but judging by the giggles from the audience they had not forgotten the blunder.
Countdown airs weekdays on Channel 4 at 2.10pm.