Laura Prepon and Ben Foster Are Engaged See Her Gorgeous New Ring

What a way to make your red carpet relationship debut! Ben Foster and Laura Prepon hit the The Girl On The Train premiere Tuesday night, marking their first official public appearance as a couple … as well as the debut of a new diamond ring on a very tell-tale finger. Speculation was at an all-time high as she flashed the new sparkler — and as it turns out, this one is the real deal, sources confirm to PEOPLE.

Laura Prepon and Ben Foster Are Engaged! See Her Gorgeous New Ring

If this is the first time you’ve even heard about these two dating, you’re not alone. It was only back in the middle of July when we wondered if the pair were officially an item as they were first spotted out and about together in N.Y.C. But the Orange Is the New Black actress has known her fiance since she was 18 — so they have plenty of history behind that brand-new bauble.

Apparently, when this couple decided to make their ‘ship status official, they decided to make things really official. Laura arrived at the film premiere wearing a turquoise lace dress with a partially sheer skirt that hit just below her knee, as well as earrings, a necklace, and a bracelet from Forevermark Diamonds, and a large round solitaire on a thin pave yellow gold band. And that makes her the second OINTB star to debut a new engagement ring this week — making us think there may be something in the water at Litchfield.