Prepon — who plays Alex Vause, Piper Chapman's on-again, off-again girlfriend in the Netflix series — debuted the bling Tuesday night (October 4) alongside new fiancé Ben Foster at The Girl on the Train premiere, People reports.
The couple have kept their relationship relatively private. Despite being photographed together last June, this was their first ~official~ appearance on the red carpet. Foster is friends with Danny Masterson, who co-starred on That '70s Show with Prepon, so they likely met through him. Here's a throwback photo of them in 2010:
Keep your fingers cross for a full '70s reunion at their wedding!