The Academy Award-nominee (for 2005's "Corpse Bride") believes his inexperience with traditional theater allowed him more creativity when turning the musical hailed by many as Sondheim's best work into a movie.
"I loved the show but I didn't know much about [Sondheim] or musicals so I was a bit naive to it and I think that actually helped me to not feel so nervous about doing [the film version,]" Burton said.
And for all the Broadway faithful -- Sondheim did give the movie his blessing.
"[The show's] been around for so long that he understood it was a movie so he accepted the fact that things would change and we'd do things you wouldn't ordinarily do on stage," Burton said.
Johnny Depp has become a mainstay in Burton's movies. Staring with "Edward Scissorhands" in 1989, "Sweeney Todd" marks the duo's sixth collaboration.
"As soon as I met [Depp], I knew he was right for the role [of Edward Scissorhands]. I didn't know the guy at all but I just felt like he was in this show '21 Jump Street' and people were looking at him like a teen idol and you just got a sense that wasn't in his heart and soul and so for me he very much mirrored what the Scissorhands character was," Burton said.
That character has led to many memorable roles in Burton's movies.
"He's a character actor; he's not a leading man. I've worked with him six different times and he was like six different people," he said. "He doesn't like looking at himself. ... He just gets in there and inhabits a role and … it just energizes everybody."
You can catch Johnny Depp in "Sweeney Todd" in theaters starting Friday, Dec. 21. For Tim Burton's entire interview with Peter Travers, please tune into ABC News NOW.