Tell me about the kind of changes you made from the book. I noticed that, like Rihanna, Tip is from Barbados. Was that added in or was it a weird coincidence?
I wanted to get the story bigger and larger than simply taking place in the United States, as it does in the book. And while we retain very much the character of Tip in the book, Tip is of African-American heritage in the book. But I love the Caribbean, I love all the melting pot of cultures there [and] we thought since Tip was the last human on Earth, how great if she sort of represented all of us. And there's very few places that you can point to that have that influx from four different continents -- South America, Africa, Europe and North America -- the Caribbean is just an incredible cultural area.
So we made a list of young actresses from the islands in the Caribbean, and at some point somebody said, "You know, Rihanna is from Barbados," and we all laughed because she would never do an animated film. But we made the call and it turns out she loves animation and was looking for a step into acting and agreed to do the movie.