Complex sentence: Although a third film was originally planned, as Emma Thompson stated previously in an interview on "Friday Night with Jonathan Ross", the box office returns from the second film were determined to be too low to go ahead on the third film.
Split into simpler sentences: Although a third film was being planned as Emma Thompson stated previously in an interview on "Friday Night with Jonathan Ross". However the box office returns from the second film were determined to be too low to make the third film.