Amanda, 49, wore a silk floral dress that featured a daring leg slip and very low cut top half.
The figure hugging outfit appears to have left fans divided on Twitter.
Some seem in awe of the flowery number, while others slammed it as "inappropriate".
One viewer appeared to take particular offence to Amanda wearing the dress pre-watershed.
"Why be so easily offended"
The One Show airs at 7pm, and this viewer described it as a "family show".
The user tweeted: "#theoneshow Why is Amanda Holden allowed to wear such a revealing dress on The One Show, supposedly a family show?"
Another defended her outfit of choice with: "She’s showing a bit of her body which 50% of people have. Why be so easily offended."
However, another user appeared just as disgruntled by Amanda's choice: "Does Amanda Holden understand that The One Show is on under the watershed of 9pm.
"She needs to ask a question to herself, is wearing a dress that is such low cut showing most of her boobs appropriate for that time of evening. It is a dress for a night club not a family show."
Another vented: "What the hell was Amanda Holden thinking of wearing that risky dress on a family show as The One Show."
A further user tweeted: "#theoneshow Amanda always looks stunning! Love her dress. So glad she gave the mother and daughter the golden buzzer. Well deserved. They sang beautifully."
"It is a dress for a night club"
Another praised Amanda's pristine appearance despite lockdown restrictions: "Just spotted @AmandaHolden on #theoneshow with a perfect spray tan, manicure and coloured/styled hair. Please do share your secret Amanda #COVIDLockdown."
And yet another urged Amanda to ignore the "haters": "You look perfect for a family show, your dress looks lovely and you look fab!! Don't listen to the haters, they have nothing better to do."
She appeared on the popular BBC show to promote her charity single for the NHS.
She also opened up on the hilarious comments recently made by her eight-year-old daughter Hollie.
When speaking about Simon Cowell and partner Lauren Silverman to her some 1.8 Instagram followers, Hollie interjected by saying: "I thought they broke up?"
But Amanda said there's no truth to it, and called her a "little sausage".
On The One Show, Amanda joked: "Poor old Hollie. Who quotes an eight-year-old?"
Host Alex Jones joked: "It was just an innocent comment," to which Amanda agreed with: "Yes. Little sausage."
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