A source told the publication, "The family is really happy about Scott and Kourtney's engagement but they're trying to keep it a secret so it's a huge surprise on the show."
But Kardashian, mother to Disick's 14-month-old son Mason, has laughed off the rumor with a post on her Twitter.com page.
She writes, "WOW!! Where do the mags come up with this stuff? And claiming exclusives? Come on now."
Asked directly by one of her followers if there is any truth to the engagement news, she responds, "Absolutely not! This is crazy!"