The TV judge chose the satin leopard print number from Miss Sohee for the latest episode of the talent contest, teaming her look with sky-high platform heels from D'accori.
She pulled her blonde hair back into a half-up style with wavy texture, and added diamond jewellery from Aariya – a brand also loved by Holly Willoughby and Nicole Scherzinger.
Sharing her usual Instagram post to show off her outfit, she simply captioned it: "Live Show 3 @bgt," with a black heart emoji.
Plenty of fans were in love with one particular detail of Amanda's outfit – her shoes! Amanda's platform pumps cost £950 from designer D'accori.
"Ohh the shoes!!" one fan replied, while another added: "Those shoes!" and another wondered: "How on earth do you even stand up in those shoes!"
Amanda has already worn two other show-stopping outfits on the Britain's Got Talent live shows, wearing a sheer floral beaded number on Tuesday evening and a corseted yellow latex gown on Monday.
As always, Amanda's BGT looks are put together by her loyal stylist Karl Willet. Sharing the star's incredible yellow look on Instagram, he wrote: "My yellow latex dream Barbie… custom design by my genius and long-term friends Atsuko & Simon."
The star has previously spoken openly about her unapologetically sexy wardrobe. Speaking exclusively toHELLO!, she said: "I don't see it as a bad thing. I think it's an incredulous thing. I think that people can't believe it.
"Not necessarily me, but people can't believe that there is this whole new generation of trailblazing women who really don't give a [expletive], who are setting the standards for literally everyone behind them.
"Because it's never happened before. I mean, my grandmother looked great at 50 but felt she had to dress in a certain way and then stop dying her hair around the age of 56 or 57, because she didn't want to be seen as 'mutton dressed as lamb'."
She added of her BGT looks: "I'm all about the theatre of Britain's Got Talent. For me it's just about making an entrance and being your super-glam best... and then when I get home, leaving it in a pile on the floor and getting into bed!”
Of her husband Chris Hughes' reactions to her on-screen outfits, she added: "He always goes, 'Why can't you come in and keep it all on? Why do I get the worst end of the deal?' I get it all off, put my stripy jammies on, or one of his T-shirts, and get into bed."