Watch The Avengers Cast Identify Each Other by Their Biceps

On screen, they’re Earth’s Mightiest Heroes. Off-screen, they’re one of the closest casts in a franchise film. But can the actors behind The Avengers do the impossible task of identifying their co-stars’ muscles? In a welcome reprieve from the onslaught of sometimes tedious Age of Ultroninterviews, the cast sat down with MTV’s Josh Horowitz to play a game of “How well do The Avengers know their biceps?”

After being shown photos, the cast was asked if they could figure out the identity of their co-star. Some of the pics were easy—apparently everyone knows Mark Ruffalo’s defining features—but some, like Scarlett Johansson and Chris Hemsworth, were harder. The one photo that stumped everyone? The man behind Tony Stark: Robert Downey Jr.

“That’s me, right?” asked Chris Evans, after being shown the photo. “That looks like Evans,” added Johansson, going for the obvious. It was finally Cobie Smulders who got the answer correct… and afterwards, Evans couldn’t contain his surprise.

This article originally appeared on EW.com.