Stealing the show - and not just with her vocals - Alexandra wowed in the style stakes in a crop and pencil skirt combo.
Don't you just love her look?!
Turning up the glam for the evening, Alexandra teamed a cleavage-baring crop top with a stylish leather pencil skirt.
The 26-year-old covered up from the cold with a chic black cape, finishing off her outfit with an intricate pair of barely-there sandals.
Nailing things on the beauty front too, Alexandra styled her long brunette locks into voluminous curls, wearing plenty of gloss on her lips and a shiny red polish on her nails - injecting a pop of colour to her all-black ensemble.
Not only did the star attend the awards hosted by the Daily Mirror and the RSCPA, but Alexandra also took to the stage to showcase her impressive vocals for the guests.
Tweeting ahead of her performance, she said: "Performing 2 songs tonight at Animal Hero Awards with @RSPCA_official !!"
Alexandra's appearance in London comes after she recently visited the X Factor studios.
Heading back to the show that shot her to stardom in 2008, Alexandra met with Mel B's final boy in the competition, Andrea Faustini, to help him perfect his performance.
And, after performing Andrea's song choice Whitney's 'I Have Nothing' week in week out for The Bodyguard musical, there was noone better to offer the Italian some helpful advice.
Meanwhile, Alexandra has openly said she would love to duet with X Factor's Fleur East.
After singing with Beyoncé during the X Factor final six years ago, the 'Bad Boys' singer revealed she has only sung with male singers ever since.
Now itching to duet with another female star, Alexandra has admitted she would love to join forces with Simon Cowell's finalist.
She said: "It would be nice to have some girl power, plus [Fleur] can dance! We could dance together and have a fierce performance."
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