Move over, Kim. There’s a new sex tape star in the family: The tight-knit Kardashian Clan willl likely be none to pleased at the revelation that baby bro Rob Kardashian is doing the horizontal mambo with adult film star Lisa Ann. The buxom brunette — who stars in the hit Sarah Palin XXX spoof Who’s Nailin’ Paylin? — even accompanied the Keeping Up With The Kardashians silver spoon to sister Khloe’s September wedding to Lakers star Lamar Odom.

“Rob treats me like his little teacher and we have a fun sexual relationship that is simple and carefree. He brings out the total cougar in me and I just like to teach him things,” Lisa Ann gushes of the couple’s burgeoning romance.

Rob previously dated ex-Cheetah Girl and 3LW singer Adrienne Bailon.