The 30-year-old reality star and Disick mocked the salacious story in back and forth tweets Wednesday on Twitter. Star magazine claimed Kourtney Kardashian accused Disick of having sex with her 19-year-old half-sister in an article earlier this week.
"I'm really [expletive] about this whole @Kendall Jenner and @ScottDisick thing!!" Kardashian wrote. "Scott, I thought it was you and I that was having the affair!" Disick responded by joking, "Don't worry @khloekardashian, You will always be my number 1."
Kardashian and Disick have weathered their own share of relationship reports due to their close and sometimes unusual interactions. The pair were the subject of a Life & Style affair article in November 2014, which the reality star subsequently mocked on Twitter.
Disick and Kourtney Kardashian have been an on-and-off couple since 2006, and welcomed son Mason in December 2009. Daughter Penelope followed in July 2012, and Kourtney gave birth to son Reign in December 2014.