More than half a million tickets have already been snapped up by people desperate to see the film first, even though it isn't out for more than two weeks.
But the people in charge of Britain's cinemas told us that there are plenty of seats left - and they're showing the film as often as possible.
A showing every hour
UCI Cinemas said Harry Potter and the Philosopher's Stone shows will be starting once every hour in most of its cinemas.
It's the same story at Odeon Cinemas, with the film being shown four times a day in most theatres.
The cinemas admit that business bosses are buying lots of tickets, but that the amount is very small compared to the millions still available.