Real age of Zac Efron in The Derby Stallion
In the movie The Derby Stallion, Zac Efron was:
17 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 The Derby Stallion was released:
January 1, 2005
And the day in which Zac Efron was born:October 18, 1987
Since movies usually don't take more than one year to be released since the beginning of the filming process, Zac Efron may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.