 Visit smiletrain.org to learn how Smile Train is supporting the cleft community with lifelong smiles. Smile Train, changing the world one smile at a time. Hey, I'm Mark Wahlberg, and this is my co-star, Arthur. What happened to you, boy? My new movie is based on the true story of a dog who treks hundreds of miles to find someone to love him and ends up showing the whole entire world how extraordinary he is.