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The 24-year-old reality TV star shared the exciting news on her Twitter page by posting a series of romantic snapshots from the couple's holiday in the Maldives.
"Me and @Gregshepherd_ are so excited to announce...," wrote Billie above a photo of the words "We're engaged" written in the sand. The post was immediately retweeted over 2,000 times within the hour and sparked a flurry of congratulatory tweets.
It looks like Greg had made every effort to give five-months-pregnant Billie the most romantic proposal ever, which she proudly shared on Twitter.
In one photo, the setting of the idyllic proposal is clearly seen as Billie captioned it, "The sand bank where it all happened... maldives #engagement #excited." Two wicker chairs and a table are set up on the beach, complete with a bottle of champagne hidden in the sand.
The Essex beauty posted more photos of the couple's hotel room showered in red rose petals. In one snapshot, a close-up of Billie's cushion cut diamond ring is seen against a background of red and pink flowers.
"So so so happy to be engaged xxx," wrote the star.
Billie shared more photos of their bed covered in petals in the shape of a heart, and a gorgeous bouquet of red roses is spotted in the background. The bathroom was equally decorated with petals floating atop a hot bubble bath.
The blonde bombshell made her second exciting announcement of the day, revealing the sex of the couple's first child.
"I'm sooo excited to be having a beautiful baby girl !! xxx," she wrote on Twitter.
Billie and her ticket broker fiancé, who she revealed had cried at the proposal, have been together for two years. When news of Billie's pregnancy was announced in January, the couple were said to be "over the moon."
"They love each other to bits," an insider told The Sun. "Billie and Greg have always been seen as the ideal couple as they get on well and they don't have all the dramas like everyone else on the show."