Her co-host Phillip Schofield shared the news of Holly's gaffe on his Instagram Stories.
Uploading a video of the pair after they had appeared on Good Morning Britain but before This Morning started, Holly was seen looking red-faced.
Phil explained: "This is one thing that shows presenters should not be allowed to dress themselves."
He then panned the camera to Holly, who explained what had happened.
"So I’m dressed, ready to go, I was just on GMB, then my stylist texted me," she revealed.
Holly continued: "She said: 'Morning, loving the show. One thing, the buttons on your right arm are covered in a coating. I think it might be tissue paper."
The presenter then held her arms up to the camera and showed off the difference between the buttons on the sleeves of her jumper.
"There’s the shiny ones," she said, before moving the camera to the buttons coated in white tissue paper.
"I’ve just gone on telly like that," she laughed.
Schofe added: "We seriously should not be let loose on our own."
Holly's pale blue jumper – which has gold buttons on the sleeves – costs £75 from Hobbs.
She recycled a faux leather skirt with a frilled hem from Warehouse.
In a bid to keep the show on air for as long as possible, all non-essential staff have been sent home.
So I’m dressed, ready to go, I was just on GMB, then my stylist texted me.
As per social distancing measures amid the coronavirus pandemic, the presenters have been styling themselves and doing their own hair and make-up.
"Happy you're still on"
Viewers are pleased the show and their favourite presenters are still on air.
Commenting on Holly's Instagram, one said: "So happy you’re still on! Please please stay safe lovely."
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Another noticed that the style of Holly's pictures has changed because This Morning is operating with a skeleton crew.
"Is it daft that I prefer these Holly selfies to the daily pics presumably taken by a staffer?" said one.
"Plus what a lovely smile," the Holly Willoughby fan added.
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