The judge, who gave birth to daughter Azura Sienna just five months ago, was radiant in the cream cropped number that she paired with a beige, high-waisted skirt.
A pair of nude heels finished the look. Her long, ombré locks had been straightened and her make-up included a dramatic purple lip.
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Alesha recently opened up about getting back into shape following her pregnancy, revealing that she hadn't been dieting. "I haven't been obsessively training or dieting," she said.
"I wanted to let natural take its course. I'm still nursing so I want to make sure that I'm good to myself. I always try to eat healthily, but I've not deprived myself of anything.
"I think I've got a lot of energy and probably that's what's helped me burn it off."
Alesha announced the news that she had given birth to her first child back in October of last year, calling her daughter "the best present in the world".
"My baby girl Azura Sienna was born last week!!! I'm elated and over the moon :) x x x x x x x x x x x x x x x x x x x x x," wrote Alesha.
The pop singer then explained what may have seemed like a sudden arrival to her fans, posting, "It seems quick because I was hiding it for so long!!! I was in my 6 month of pregnancy at the Britain's Got Talent final! :) xxx."
The newborn is the first child for Alesha and her dancer boyfriend Azuka Ononye, who she met in 2006 when he worked as part of her backing team.
Friends say that Nigerian-born Azuka helped the songstress to get over her heartache, after Alesha found out that her then-husband, MC Harvey, had cheated on her. Alesha divorced the rapper that same year.
A spokesperson for the former X Factor star confirmed Alesha's pregnancy in June, after rumours emerged that she was expecting when she made two toasts "drinking water instead of wine".