The film premières on Sunday in London
Harry Potter And The Philosopher's Stone has already attracted the UK's biggest-ever advance ticket sales, cinemas have reported.
The Odeon group has dedicated nearly half of its total 599 cinema screens to showing the film - and has also trebled its number of call centre staff.
Marketing director Ron Hanlon said: "The excitement surrounding this film is
phenomenal and our call centre has never been so busy.
"There are still plenty of tickets available across the country, so everyone will get the chance to see Harry Potter on the big screen."
'Biggest sale'
Warner Village, which will be showing it at more than 150 screens, also said that interest in the film was unprecedented.
The chain had already sold £616,000-worth of tickets, which a spokeswoman described as "the biggest advance sale we've had".
UCI spokeswoman Vicki Locke said: "The evening performances are as busy as the daytime ones, which shows that the film appeals to both adults and children, just like the books."
Harry Potters' popularity has been confirmed in a new poll by the book-selling chain Waterstones.
For 22% of the 1,000 adults surveyed, Harry was the first fictional character that came to people's minds - compared with 2% for classic literary characters like Sherlock Holmes.
And 42% were able to identify the characters Harry, Hermione, Ron, Hagrid and Dumbledore as being from JK Rowling's series - while only 26% were able to identify Enid Blyton's creations Julian, Anne, George, Dick and Timmy.
Lesley Miles, marketing director of Waterstone's bookstores said: "Harry Potter is now clearly established as one of the best known characters in fiction.
"It's fascinating to see how his popularity just keeps growing."
The world première of Harry Potter And The Philosopher's Stone is at the Odeon Leicester Square in central London on Sunday, and goes on general release on 16 November.