After wrapping the romantic movie, Bana shaved his head for his role as Nero in recent sci-fi release Star Trek.
Director Robert Schwentke realised he needed Bana to reshoot scenes with co-star Rachel McAdams for The Time Traveler's wife, only to discover he looked completely different.
The delay means the film is hitting cinemas in the U.S. this week (14Aug09), a year after its original release date.
McAdams explains, "We wound up doing a reshoot, but Eric had to shave his head for Star Trek. Basically we were waiting for Eric's hair.".