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. >> and he's up all "nightline" talking with "elf" director jon favreau about making movie christmasic. >> santa's sleigh! >> you're going to help me make itly thermal coupler. >> reporter: at the beginning of the movie "elf," it's becoming clear to will ferrell's character buddy that he's not exactly the santa's helper that he thinks he is. and there i am playing the boss, calling out buddy for being the worst toy maker ever. >> that boys you 915 off the base. >> reporter: jon favreau directed the story of a human raised by santa's elves at the north pole. >> part of why i asked you to cameo in the film was because i wanted some of the christmas story, that good mojo, that was our goal. we were half joking, saying, maybe this will be like "christmas story. >> reporter: it wasn't the only source of inspiration. john studied classic tv christmas specials like this one, which like its name sake has gone down in "rudolph," made in 1964, was painstakingly shot with puppets, and is the longest running tv special of all time. >> buddy the elf was a kid that grew up in a christmas special.

reporter: then there's "elf" which featured a cameo from peter billingsley as his pal director jon favreauybe this will be like "christmas story" like every year you'll watch it. >> reporter: let the binge-watching begin. for "good morning america," chris connelly, abc news, los angeles. [ cheers and applause ] >> we've got peter billingsley here with us right now and, peter, this "20/20" special, it goes behind the scenes, classic holiday s we all love and you were in "a christmas story." give us something we don't know. >> well, there was one scene truly -- i'll give you something i never talked about before. one scene that never made it to the movie. a huge fantasy scene there was a lot of those in the film but there was a big one in outer space and ralphie saved flash gordon in a huge space scene but it was ultimately too much for the movie. it was cut and unfortunately it was before dvd so it's lost forever. i think there's one still out there if you deep dive on the internet you can find me with me in a silver little set of shores which isn't too flattering. >> i'm going to look for