The reality TV star, 23, found her belly was a little rounder and couldn't resist sharing a picture with her friends and loyal fans on social media.
Alongside a picture of herself in the mirror, mum-to-be Billie wrote the caption: "Oh hello #babybump ... It appears you have grown over night … Haha."
In the snap, Billie's unborn baby girl can be seen clearly in a blossoming bump under Billie's super-cute heart motif grey dress. She is also wearing a grey furry gillet and grey leggings.
Fans of Billie shared their happiness for the pregnant Essex girl, with one calling the post "adorable" and another saying: "Ur gonna be the best mum ever x."
In the first episode of The Only Way Is Essex's eleventh series (23 February), Billie is seen having an ultrasound scan with fiancé Greg Shepherd by her side.
After being told she is expecting a baby girl, a newly-engaged Billie goes home to tell her family and friends.
Too, too cute!
The Only Way Is Essex airs Sundays and Wednesdays on ITV2.
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Check out the other celebrities who have become engaged in 2014 like Billie Faiers and Greg Shepherd:
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