File this under: Things aren't always what they seem.
Well, now we have confirmed the ring is from the Bulgari Serpenti collection. A rep for the brand tells E! News it is "18-karat pink gold with 2.51-carat diamonds and rubellite."
It's highly unlikely that the former Fringe actor would present his ladylove with something that wasn't one-of-a-kind (i.e., not from a collection). So it appears the fashionista—who has worked with Bulgari in the past—could have simply been donning the jewelry on her left hand by sheer coincidence.
As for whether or not the couple are truly engaged is an entirely different matter. During the summer, reports surfaced that the pair were very close to making the leap. But nothing has been confirmed or denied.
Looks like the duo is going to keep us guessing for just a little while longer.
—Additional reporting by Ruth O'Neill