Los Angeles - Khloe Kardashian lost her virginity when she was 15.
The Keeping Up with the Kardashians star told her sister Kourtney Kardashian, 36, the age she was the first time she had sex during a video clip of the sibling's playing a game of 'Know Thy Sister' for the brunette beauty's website (kourtneykardashian.com).
During the clip, Kourtney, said: "We are going to play a game called Know Thy Sister, a question is going to pop up and we have to see if we know the answer."
She then asked Khloe when her first sexual encounter was and the blonde beauty wrote down on a whiteboard the number 15.
And Khloe, 31, added: "I think it was 15?"
Elsewhere in the game, Kourtney was asked when her first lip-locking session was and she said it was "a late first kiss".
The mother-of-three was shocked when Khloe asked her if it was in fifth grade she had it.
She responded: "What? Who do you think I am?"
However, Kourtney - who has Mason, six, Penelope, three and Reign, 14 months, with ex-partner Scott Disick - clarified and teased that while she was late to kissing she did other stuff with boys, which "made up for it."
She told her sister: "I remember it being a late first kiss. But I made up for it by doing more than just kissing."