If you saw The Social Network this weekend then you probably walked out talking about the scene-stealing Winklevoss twins, identical brothers. The special effects to create the doppelgangers are created so seamlessly that you’d never guess that one actor, Armie Hammer, played both parts… sort of.

Hammer’s been getting a lot of credit for successfully playing a dual role in the film as the scene stealing brothers, but in fact, he didn’t do it alone. The Washington Post has an interview with actor Josh Pence who played the other Winklevoss twin. The Winklevoss special effect was created by having Pence play one of the brothers in scenes where both Tyler and Cameron Winklevoss are together. Armie Hammer played the other Winklevoss, and then after filming was complete David Fincher’s team went in and erased Pence’s face, replacing it with Hammer’s.

This was more than just a stand-in role for Pence, it sounds like he actually acted the part and went through everything Armie Hammer went through, even though Hammer’s face is the only one you’ll see on screen. The two worked with an acting coach together for ten months, trying to develop the identical movements and speech patterns that the real life twins would have. Armie Hammer will get all the credit, but Josh Pence is there on screen. Well 3/4s of him is anyway. Everything but his face.