The model and actress' black wraparound gown turned see-through under the camera flashes, giving everyone a good look at her most famous assets. Oops.
Kelly, however, didn't seem too bothered, happily retweeting a picture of her red carpet look to her fans. The fan who'd tweeted the image at her had added the caption: "Phenomenal, simply phenomenal" and a kiss icon.
Not only did Kelly's dress attract plenty of attention thanks to its plunging neckline, it also gave us a very Angelina Jolie-esque thigh high split and exposed Kelly's back.
The brunette was at the NTAs to support Celebrity Juice, which was nominated. She stepped in as a team leader last year while Fearne Cotton was on maternity leave.
Celebrity Juice was beaten to the 'Entertainment Programme' prize by I'm A Celebrity… Get Me Out Of Here!, but that didn't seem to dent Kelly's night, as she was seen with a huge smile on her face all evening.
Kelly's rumoured new boyfriend David McIntosh wasn't with her at the glitzy show.