Mark Ruffalo has received critical acclaim for his dual performance as twin brothers Thomas and Dominick in the harrowing HBO miniseries I Know This Much Is True . In addition to the usual green-screen acting challenges that come with playing multiple roles, Ruffalo created a clear physical distinction between his two characters; neurotypical Dominick is visibly thinner than his brother Thomas, who is schizophrenic.
Mark Ruffalo Did 500 Pushups a Day to Lose 20 Lbs
Ruffalo has previously explained how he and director Derek Cianfrance agreed that he would shoot all of his scenes as Dominick first, and then put on 30 pounds to play Thomas, to illustrate the weight gain that many people experience when on anti-psychotic medication.

In a recent interview with The Wrap , Cianfrance said that Ruffalo lost 20 pounds first in order to play a noticeably thinner Dominick, and was doing "probably 500 pushups a day" during the first 17 weeks of filming. "My very first meeting with Mark, I told him that if we were going do something like this, I couldnt imagine us shooting in the morning, breaking for lunch and having him putting on a wig or a fake goatee and playing the second half," the auteur explained.