Real age of Robert Duvall in 1918
In the movie 1918, Robert Duvall was:
53 years old
That was the real age of the celebrity according to our calculation.
The calculation of the shown age took into account the first day of the year in which the movie 1918 was released:
January 1, 1985
And the day in which Robert Duvall was born:January 05, 1931
Since movies usually don't take more than one year to be released since the beginning of the filming process, Robert Duvall may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.