- Laura Prepon and Ben Foster made their red carpet debut Tuesday night
- The couple were first spotted together this summer in NYC
- Prepon's 'OITNB' co-star Samira Wiley also announced her engagement this week to Lauren Morelli
(CNN)Laura Prepon and Ben Foster are engaged.
The couple made their red carpet debut at the LA premiere of "Girl On The Train," and Prepon flashed a massive canary diamond engagement ring. Fans were completely shocked, so no one knew they were dating.
The actors were spotted strolling through NYC this summer, but since then they've kept their relationship under wraps. Prepon stars in "Orange Is The New Black," while Foster has starred in movies including "Lone Survivor" and "X-Men: The Last Stand."
This is the second engagement this week for the cast of OITNB. Prepon's co-star Samira Wiley got engaged to one of the show's writers, Lauren Morelli. Wiley confirmed the news on her Instagram account Tuesday with a snap of her new sparkler.
Morelli was actually married to a man when she met Wiley, but the couple have been dating since 2014. She revealed in an essay for Mic that she discovered she was gay while writing love scenes for Taylor Schilling and Prepon.
"I was so deep in my own self-doubt that I constantly felt like a fraud," Morelli wrote. "I was sure it was bleeding into my writing. How could it not? I was married to a man, but I wasn't straight."