The blonde presenter seriously cranked up the heat on today's dose of the Channel 4 quiz show.
But it wasn't just Rachel's dress that caught viewers' attention.
The 31-year-old also revealed how she was moments away from death on a family holiday at age 14.
She revealed: "I was rescued once from the sea by a lifeguard.
C4SHOCKING: Rachel revealed she almost drowned when she was a teenager
"I was taken under and thought that was it."
Rachel added: "I was calmly like 'Oh, there's not much I can do about this' and then was dragged out by someone who saved me."
The maths and brain beauty dropped the drowning bombshell when host Nick Hewer asked about holiday disasters.
C4STUNNING: Rachel flaunted her figure in a bright pink dress
“I was rescued once from the sea by a lifeguard”Rachel Riley
Predictably, though, viewers at home were too busy ogling the beauty's bod to engage with her tale.
Rachel flaunted her toned bod in a magenta skater that fell right above the knee.
And if that wasn't enough of a tease, the cheeky show-stopping number boasted a lace v-neck front that paraded her breast assets.
One person tweeted: "I've been watching Countdown since I started traveling to and from the UK a year ago. You're so cute! And smart as hell!"
C4DISTRACTED: Viewers were more interested in Rachel's killer outfit
"Miss Riley perfect in pink today," added another.
A third complimented: "Rachel Riley on Countdown today," with a heart-eye emoji thrown in on the end.
Catch Countdown weekdays at 2:10pm on Channel 4.