Former X Factor star Rebecca was performing at the Symfunny charity concert, held by Parkinsons UK and wowed the crowd - including TOWIE's Jessica Wright and Ricky Rayment - by singing 'Amazing Grace'.
Rebecca, who is expecting her third baby, chose to wear a gorgeous black cutout gown to the event, and it showcased her pregnancy curves perfectly.
Following the show, Rebecca tweeted: "Off to bed brilliant night great cause, amazing organisers."
In April, Rebecca confirmed her pregnancy to fans, adding that she felt "grateful" to be expecting another baby.
Just weeks earlier, Rebecca had fainted during an earlier appearance on Loose Women, however her pregnancy was still a secret at that point!
The Liverpudlian lass, 27, is already mum to two children, Lillie May and Karl, from a previous relationship.
Celebrities who have announced pregnancies in 2014:
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