By CASSIE CARPENTER
She last shared a candid snap of herself during a painful-looking dental examination.
But Bar Refaeli decided to remind the world why she's one of the most in-demand bikini models by posting a Twitter picture of herself topless while submerged in water Monday morning, with the caption: 'Watch your back!'
In the sexy black & white shot, the 27-year-old stunner can be seen from behind wearing nothing but a checkered string bikini bottom - with visible tan lines - as she coyly holds her triangle top.
However it's unclear when the cheeky picture was actually taken or whether the Israeli model is in a swimming pool or the ocean.
Bar also posted a mysterious picture of herself with five small children, and wrote: 'Can u think of a better day to start the day?'
The five-foot-nine beauty, who recently appeared in a new photo shoot for Spanish Glamour magazine, frequently shares glimpses into her glamorous, jet-setting life with her 363,000 followers.
The Sports Illustrated cover model was last spotted a week ago in Berlin shopping at the Emporio Armani boutique with her father Rafi.
Last month, the former Germany's Next Top Model gust judge started her own model casting show called Million Dollar Shooting Star on German TV Channel Sat.1.