One viewer joked that the 43-year-old singer was “off to the beach on the way home by the looks of it”.
Alesha rose to her feet after slamming the Golden Buzzer for duo Flintz and Taylor on tonight’s show.
She was seen getting overcome with emotion during the performance, blinking back tears while Flintz sung and Taylor played the piano.
Alesha told the pair: “Nothing makes me more happy than seeing young musicians. You had something to say, Flintz.
“We’ve had no one on the show like you before, which is brilliant. They say in life: leave the best till last.”
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She then rose to her feet and hit her golden buzzer, leaving the pair hugging each other in disbelief on the stage.
The star told them: “Well done guys. Can’t wait to see what you’re going to do in the live shows now.”
Alesha wore a top with a pair of black trousers on tonight’s show, whose stars are famous for wearing daring outfits.
Alesha has attracted Ofcom complaints – albeit not many – for her outfits choices in the past.
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The chic gold and black Sergio Hudson jumpsuit she wore to one of the show’s semi-finals in 2016 received 19 objections.