He Literally Got Huge — Robert Downey Jr. as Iron Man

Downey has long said that yoga was one of the ways he recovered from, and avoids, his past addiction issues.

To prepare for his role as Iron Man, Robert Downey Jr. had to workout, but his regime was much more severe than his usual relaxing yoga exercises. Downey spent five days a week training with weights and practiced martial arts every day.

He packed on 20 pounds of muscle for 'Iron Man.' He would need it, as the original armor weighed ninety pounds.