The actor's make-up took so long that the cast members were left with a few hours each day to shoot for the movie, the ‘Contactmusic’ reported.
Pitt is born with the physical limitations of an 80-year-old man in the film, who grows young.
The role required the actor to spend up to five hours in the make-up chair each day and the process left the star so exhausted that he would head to bed as soon as the shooting was over.
"If the make up fails, the movie fails. It was all important to get it believable and be able to put it on in a length of time that still allowed you some hours to shoot," Pitt told UK's Film 2009.
"When we finally got a shot that we thought 'That's done', everybody slept for at least one weekend!," he added.
The star has been nominated under the Best Actor category for his role in the film, which is leading the Oscars race with 14 nominations.
