Naughty Fearne Cotton was forced to apologise to radio listeners after she was caught getting all sweary on air.
The Radio 1 presenter was hosting a Christmas edition of the Live Lounge when she turned the air blue.
Online live-feed listeners who had tuned into the special show featuring Cheryl Cole, Ricky Gervais and Jamie Oliver heard Fearne's gaffe when a mic was left on.
As Wizard's festive hit, 'I Wish It Could Be Christmas Everyday' played, Fearne could be heard telling Cheryl Cole not to swear before doing exactly that herself!
“No swearing and don’t make any w***** gestures because people will see them on the webcam,” she said.
Fearne quickly apologised after realising her mic was still on, saying: “We might have heard some bad language on the radio because one of the mics was still faded up in the kitchen.”
We always wondered how Cheryl managed to sing so perfectly whilst throwing some serious shapes to her No.1 single 'Call My Name'. Now, thanks to her performance on 'Stand Up To Cancer', we know.
Jessica Simpson's little sis, Ashlee, didn't even pretend to mime along to her hit 'Pieces Of Me' on Saturday Night Live back in 2004. She just did it a little jig instead to try and distract us from the fact that she was going to mime along to her single. Yeah, that's do it, Ash.
Britney made hardly any attempt to hide the fact she was miming when she appeared on 'The X Factor' to perform 'Womanizer' in 2010. As if her out-of-time lip movements weren't enough, Dermot O'Learly gave the game away by handing Brit a mic to talk into after the performance. D'oh!
Mariah forgot to put her mic to her mouth in time for her big screechy note when she appearing on 'Ant & Dec's Saturday Night Takeaway'. Ooops!
All About Eve
We can't remember any of All About Eve's songs but we DO remember sitting down to watch Top of the Pops back in the day and seeing Julianne Regan and Tim Bricheno sitting there like lemons as their single 'Martha's Harbour' played but they failed to hear it. Despite the epic live telly fail, the single climbed the charts for the next two weeks!
If the acting work ever dries up for Li-Lo (which can't be that far off) you'd think she'd have her music *ahem* career to fall back on but she's going to need to brush up on her lip-synching skills first.
Cheryl Cole (again)
She may have prepared a backing track with live vocals recorded over the top, but Cheryl was fooling no one when she performed 'Fight For This Love' on 'The X Factor' in 2010.
Katy Perry: Singer, songwriter, dancer... recorder player? Errrm, no.
The 'X Factor' contestants
The 'X Factor' contestants have long made us cringe with their dreadful mimed group performances, but this particular rendition from 2011 had our toes extra curled.
Beyonce fooled us all with her rendition of 'The Star Spangled Banner' at President Obama's inauguration. And she would have got away with it if it wasn't for some pesky kids who outed her as having mimed.
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