The seasonal animated movie, which featured the voices of Bill Nighy and James McAvoy, was a huge hit at the U.K. box office in 2011, reaching number one and pulling in $147 million (£91.9 million) in ticket sales.
The film's characters made up part of the huge festive decorations which light up central London, and Smith admits seeing the display was the best part of her filmmaking process.
She tells Denofgeek.com, "It was great! The best thing was because we had the Regent Street lights, I felt like someone had decorated London to be my own personal Christmas tree! All these characters that you've loved and lived with, and there they are being the city's decorations! It's fantastic!
"Do you know, that was the best thing of the entire experience. It was such a lovely and delightful thing.
"I had in mind that when it came out, I would go and watch it in a few random cinemas. But I didn't, because you always have a slight worry watching a film with an audience, you worry whether they're going to laugh. So you don't really sense the idea that people are seeing the work that you've done. But, of course, walking down Oxford Street, there it is. All these characters that are terribly personal are suddenly out there in the world."