Robert Downey Jr amused by Rourke`s acting technique

London: Hollywood hunk Robert Downey Jr was left baffled on the set of upcoming movie `Iron Man 2` after his co-star Mickey Rourke asked for pictures of his dead dogs to be held up while filming emotional scenes.

Downey Jr is reprising his role as the superhero for the sequel, which will see his character pitched against villainous Whiplash, played by Rourke. The 45-year-old actor was fascinated by his co-star`s unusual acting technique of using photographs of his beloved Chihuahuas, a news daily reported. "He would have someone holding pictures of recently deceased pets off camera to make him feel sad or whatever for a scene. It was all serious stuff. I`ve never seen anything like it," Downey said. PTI