Rosie Huntington Whiteley Out on the Town With NOT Jason Statham

4/4/2015 8:52 AM PDT

11:25 AM PT Sources close to Rosie say everything is fine between Jason and her.  They say the ring is NOT an engagement ring ... it's a family heirloom she sometimes wears.  As for their relationship, "Things are 100% fine.  They still plan to move in together in their new home."  As for who the dude is, they say it's just a friend.

This is weird, at least on the surface.  Rosie Huntington-Whiteley was holding hands with some dude Friday night, and it definitely wasn't her rumored fiancé Jason Statham.

Rosie was leaving The Nice Guy nightclub in WeHo ... we don't know who the guy is, but they sure seem chummy.

It got our attention, because just last week we broke the story Jason and Rosie went halfsies on a $13 million Bev Hills estate.  And she's been wearing what sure looks like an engagement ring ... but last night, no ring.

Maybe it's nothing, but it caught our eye.  We contacted reps for Jason and Rosie ... so far no word back.