Real age of Jim Sturgess in 21
In the movie 21, Jim Sturgess was:
29 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 21 was released:
January 1, 2008
And the day in which Jim Sturgess was born:May 16, 1978
Since movies usually don't take more than one year to be released since the beginning of the filming process, Jim Sturgess may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.