Tarek El Moussa may have had people thinking something was up between Zac Efron and Amanza Smith from "Selling Sunset" -- but it's a red herring, 'cause there's nothing going on.
Sources familiar with the situation tell TMZ ... Amanza and Zac are not a couple, this despite posing for a pretty couple-y photo that the "Flip or Flop" star threw up on the 'Gram, which shows them cozying up in a group shot at a UFC event in Vegas.
Tarek was hanging out with UFC announcer Bruce Buffer -- whom Tarek and his wife, Heather Rae Young have known for years -- 'SS' star Mary Fitzgerald and of course ... Zac and Amanza, who ended next to each other in the pic.
A lot of people saw their placement and thought they were an item, but our sources insist ... it's simply not so. Here's what we do know about Amanza's love life -- we're told she's actually dating a pro soccer player from overseas ... and is head over heels, as she's indicated herself.
As for Zac, he was most recently dating a gal named Vanessa Valladares -- whom he met in Australia -- but they reportedly split earlier this year. So, it seems he's available.
BTW, if you're wondering how the heck Zac even fits into this reality TV bunch ... he actually doesn't. Our sources say he just happened to be at the same dinner as Buffer and the rest of the 'Selling Sunset' crew, and popped in for a quick group photo -- since he and Bruce are buds.