Yellowstone's Hassie Harrison and Ryan Bingham are deep in the throes of newlywed bliss ... with the actress now proudly taking her wedding ring out for a spin.
Video footage shows Hassie flashing her rock at the Wynn Hotel in Vegas ... at a fun-fueled after-party for Ryan following his performance at the city's Virgin Hotel Thursday.
The newlyweds are filmed singing one of Ryan's new, unreleased songs ... which sources at the bash tell TMZ he wrote for her and requested she come up on stage to sing it together.
The ring is a little hard to see at first -- with the pair gazing into each other's eyes and sharing a passionate smooch -- but as the blushing actress heads off stage with her hands up to her face, the sparkler is visible.
For added measure ... a source tells TMZ that friends and family were heard referring to Hassie as Ryan's "wife" ... so for any doubters, it looks like they're well and truly hitched!
The sighting comes days after Ryan first prompted marital speculation by sharing two snaps wearing a wedding band -- with sources telling TMZ they married in early Oct in Dallas -- Hassie's hometown.
Ryan and Hassie's relationship has been a whirlwind ... going IG official in April, purchasing a Topanga Canyon ranch over the summer, and exchanging vows a few months later.
Clearly, when you know, you know ...