Real age of Stephen King in A Return to Salem's Lot
In the movie A Return to Salem's Lot, Stephen King was:
39 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 A Return to Salem's Lot was released:
January 1, 1987
And the day in which Stephen King was born:September 21, 1947
Since movies usually don't take more than one year to be released since the beginning of the filming process, Stephen King may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.