The 28-year-old reality star exposed her nipple in a sheer purple blouse as she took to the stage for the live family-friendly broadcast show.
The Keeping Up With The Kardashians personality had opted for a plunging black long-sleeve sheer top with sequined detailing, which she opted to wear with no bra underneath. She paired the ensemble with a tight-fitting black pencil skirt cinched in at the waist with a leather belt.
Standing alongside co-host Mario Lopez, Khloe was smiling as she underwent her hosting duties, seemingly unaware of the wardrobe malfunction.
Afterwards she joked about the incident on her Twitter account, saying: 'I think I had a little nip action earlier. LOL.'
But Judge Simon Cowell certainly took note, immediately taking to his own account to make a crude joke about the incident. 'I think the air conditioning is on high tonight looking at khloe,' he wrote on the social networking site.
The exposure also caused an social-networking sensation, with several users tweeting up a storm about the incident.