Woody Woodpecker, up in a tree, pops his head through a sign that says: "Universal Presents 'Woody Woodpecker" and says, "Guess who?" He issues his characteristic laugh as he jumps down onto a lower branch. IMDb's Memorable Quotes page says that's the first line of the film. But does that really count? Woody says the same thing in the title sequences for almost all of his films.
In most of the other Woody Woodpecker cartoons, it doesn't count. But in this film, the line separating the title sequence and the beginning of the film is atypically blurred.