The reality star and mum-of-one, 25, shared the snap on Friday (13 February) - and gave us all a serious case of body envy.
In the picture, Billie - who is wearing oversized sunglasses and a nude lip colour - can be seen in a turquoise snake print bikini.
Her tum looks taut and trim, and her engagement ring is sparkling on her finger.
Alongside the picture, Billie wrote: "Bye tenereifeeeeeeee.... #towie #filming #bikini #selfie."
Unsurprisingly, Billie's fans were quick to comment, calling her "gorgeous" and "perfect".
Billie has just returned from filming new episodes of TOWIE, which ITVBe have confirmed will return on Sunday 22 February.
While there, Billie enjoyed quality time with her daughter Nelly and her fellow castmates including Ferne McCann and Jessica Wright.
On her return, the boutique owner shared another lovely snap - this time of her fiancé Greg Shepherd and their daughter having a little kiss.
In a special Valentine's Day message she wrote: "Daddy and his little #valentine..."
She also posted a romantic message to Greg, saying: "Happy valentines day to my love, my sweets, and my best friend in the whole world .... (Apart from nelly) ... love you forever xxx."
Earlier this week, Reveal unveiled the new trailer for series 14 of TOWIE which sees the castmates speculating about Chloe Sims and Elliott Wright's on/off relationship.
Are you looking forward to the new series of TOWIE? Tell us in the comment box below and you could win £50!
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