It may be nearly fifty years old, but Mary Poppins, like many Disney films, is a timeless classic that almost everyone seems to have seen at some point. Based on a series of children’s books by Australian-born author P.L. Travers, Mary Poppins won five Academy Awards and contains some profoundly memorable musical numbers and performances.

Emma Thompson, who herself played a nanny with unusual magical powers in the Nanny McPhee films, takes on the role of Travers in Saving Mr. Banks, the new true-story drama film about the author’s professional relationship with children’s entertainment titan Walt Disney (Tom Hanks), and her strong objections to the eventual finished product that was the 1964 Mary Poppins musical film. Travers was notoriously unhappy with the way that her haughty English nanny was made soft and saccharine in the Hollywood interpretation of her books, and in fact had resisted studio offers to buy the film rights for many years before finally agreeing to a deal with Disney.

Saving Mr. Banks will be out in theaters at the end of the year, and TIME has offered a first look at the lead actors in an image of Hanks and Thompson side-by-side as their respective characters. Other big names in the film include Paul Giamatti, Jason Schwartzman and Ruth Wilson, and Saving Mr. Banks was directed by John Lee Hancock (The Blind Side) from a script by Kelly Marcel (who is currently writing the script for a rather different film: Fifty Shades of Grey).

The image – showing a very disapproving P.L. Travers being taken on a tour of Disneyland by Walt Disney himself – is nicely representative of the drama at the centre of Saving Mr. Banks. Thompson seems to be an excellent casting choice for the role, which is why it’s a little surprising that she struggled so much with the challenge of playing Travers. In the interview with TIME, Thompson admits:

“She’s the most difficult person I’ve ever played… She was a woman of quite eye-watering complexity and contradiction. Often I play people who are controlled by some very clear guiding moral principles. Like Margaret Schlegel [in Howards End], guided by the early principles of feminism and equal rights, and Elinor Dashwood [in Sense and Sensibility], guided by the principles of decency and honor. There are very clear moral prisms these women pour life through, and I understand that very well. And [Travers] was not like that at all. She was far more chaotic and confused and morally various.”

Much of the heat surrounding the production of Mary Poppins was caused by the fact that Disney had offered Travers the chance to approve the film personally, as well as a $100,000 dollar advance and 5% of the overall profits. Travers offered objections to many different aspects of the film, and once it was released she was so appalled by the finished product that she refused to ever work with Disney again, or to allow them to make a sequel to the film.

There are a number of avenues that could be explored in Saving Mr. Banks, not the least of which are the possible parallels between Travers and the character that she created. Since Mary Poppins is a well-loved staple of many people’s childhoods (Dick Van Dyke’s dodgy Cockney accent notwithstanding), audiences are more likely to find themselves on Disney’s side in the on-screen struggle, but the question of how much creative control a writer should maintain over an adaptation of their work is one that Saving Mr Banks will hopefully tackle head-on.

Saving Mr. Banks will receive a limited theatrical release on December 13, 2013, followed by a wider release a week later.

Source: TIME