Kardashian Parties with Jacksons

2/23/2010 4:15 AM PST
Kourtney Kardashian took her young son Mason to a birthday party at the Jackson family home in Encino on Sunday -- turns out the two families go waaaay back.

Kourtney and her sis, Kim, used to date two of Tito Jackson's sons (Kourtney dated Taryll and Kim dated TJ) back when they were in their early teens. The party on Sunday was for one of Taryll's kids, Tito's grandson. We're told Michael Jackson's kids were there as well.

Small world.