Channel 4 viewers were in hysterics after cheesemonger Morgan McGlynn accidentally swore just as the host was apologising for her earlier bad language.
"Apparently there was some swearing on the show so we apologise about that," said the 48-year-old presenter.
Unfortunately, his oblivious guest seemed so shocked and embarrassed that she exclaimed: "Was that me? Oh s***!"
Sunday Brunch guest Morgan McGlynn accidentally swore live on air
Hosts Tim Lovejoy and Simon Rimmer burst out laughing at the swearing gaffe
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Tim and his co-host Simon Rimmer fell about laughing, while comedian Russell Brand, who was also appearing as a guest on the popular breakfast show, joked: "You're passionate about your cheese here, effing and blinding!"
Those at home instantly spotted the hilarious gaffe and took to Twitter to share their amusement.
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One person said: "Love a bit of swearing from the cheese lady."
Another thought it was hilarious that Morgan was the one swearing: "I love the fact the cheese lady swore and not Russell."
Earlier in the show, actress Amanda Redman had viewers and presenters in stitches when she couldn't stop laughing when Tim made an accidental innuendo.
Sunday Brunch fans took to Twitter to share their amusement
Some viewers called in the best ever episode of Sunday brunch after all the hilarious moments
Speaking about a trip to Sri Lanka when he had to shower outside, Tim said he remembered finding different animals looking at him and one time he saw a snake, at which point the presenter said: "I really don't want to be taking a shower with a snake."
Amanda couldn't contain her amusement and proceeded to have a laughing fit that kept interrupting the rest of their chat as the segment went on.
Tim commented to Simon: "I don't know what she's thinking about…"
The show had so many laugh-out-loud moments that several fans were calling it the best episode they had ever seen.