Bitsie Tulloch and David Giuntoli joined their co-stars at Comic-Con for a Facebook Live chat with ET's Leanne Aguilera, who at the end of the discussion noticed Tulloch wearing a gorgeous rock on THAT finger.
"It's over a hundred years old," Tulloch said of the ring. "The diamond is from the 1890s, and the setting is from 1915, which is the year my grandfather was born."
You have to give credit to Giuntoli, he knows how to pick 'em! Of the classic band, the actor joked, "I had to dig it out of the grave, it's fine..."