In the video, you can see the pair making a beeline for a waiting car last Friday night as they left LIGHT nightclub inside Mandalay Bay. Selena couldn't hide in that silver dress, while Orlando tried to slip out low key ... head down with a hat.
The video has all the makings of a sure thing -- but our Selena sources say she's adamant there were other people in the car with them ... and they all made a late night fast food run together. After that though, Selena's insisting she and Orlando went to separate corners (hotel rooms).
As TMZ first reported, the pair got super handsy at an after-party for Selena's concert.