RACHEL RILEY, who joined Countdown back in 2009, whipped her 23,000 Instagram into a frenzy recently by posing for a rare racy snap in an emerald green bikini.
The Countdown star posed on a beach in Rhodes, Greece, as she promoted Plastics Action, a campaign by Sir David Attenborough which urges people to cut down on plastic to help the environment.
Rachel Riley asked her followers to join in with the campaign, but fans were distracted by her jaw-dropping physique.
The 32-year-old showcased her cleavage in the halterneck number which struggled to contain her assets and flashed her well-defined pins.
Proving to be a natural beauty, she appeared make-up free and hid behind dark sunglasses.
Many fans of the Channel 4 maths whizz flocked to the comments section on her page to compliment the star.