Hergé has an animated cameo around the 15½-minute mark as a gangster in a hat and yellow trench coat.
While this ended up being the last episode of the animated series, the comic book "Tintin in America" is actually one of the very first Tintin adventures written by Hergé. Therefore, major characters like Captain Haddock and Professor Calculus do not appear here, as they had yet to be introduced in the series.