Mickey Rourke prepares for sad scenes by looking at his dead pets.

The veteran actor - whose beloved dog Loki passed away last year - amazed his co-stars on 'Iron Man 2' with his unorthodox way of summoning up the emotions he needed to convey in his role as Russian hardman Whiplash.

Robert Downey Jr. - who plays lead character Tony Stark - revealed: "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. But we had a great time and we were very lucky to get him."

Robert enjoyed filming with Mickey, and says they had an equally fun time together off set.

He said: "How bad-a*s was Mickey with those whips? But, really, at the end of the day, it's just two schmucks in trailers and once in a while I'd be like, 'Hey, mind if I used your treadmill?' And Mickey goes, 'Yeah, you should try my weight vest. Helps you break the sweat quicker.' And I'd be, 'OK. See you on set, bad guy', and he'd say, 'OK, punk.'