Pat Hanna's early digger sketches (those that date back to the Diggers Concert Party troupe he led while serving with the New Zealand army) comprise a variety of characters types. These comic sketches were initially based on experiences of Australian and New Zealand soldiers during the First World War. Even not-so-humorous incidents and individuals, notably officers (and very often British officers), English soldiers (Tommies), and pompous civilians were introduced, albeit by being sent up and ridiculed. Although war experiences remained a popular theme throughout the life time of the Diggers troupe, the sketches began to shift their attention towards more pressing issues from the early 1920s onwards, particularly the problems experienced by soldiers as they attempted to return to the 'normality' of civilian life.
As Hanna and his team of writers began to originate new sketches during their first tour of the Antipodes, some characters started to take a more definite shape and personality. The first of these was Chic (later given the full name of Chic Williams), whom Hanna developed as his own alter-ego. Another was Bert, played by Will Crawford. The teaming up of Hanna and Crawford as Chic and Bert is perhaps not surprising, given the long tradition of comic duos in variety entertainment. Such partnerships also allowed the performers and writers greater ability to encapsulate the ideals of mateship and larrikinism within the short narrative time afforded the sketch genre.
Following the departure of Will Crawford from the Famous Diggers in early 1923, Hanna developed a new onstage partnership with Joe Valli, as the character Joe Mulga. The pair continued to present old Chic and Bert sketches (as Chic and Joe) while also working in new material. In the early 1930s, Valli decided to create another alter ego, Jock McTavish, for Hanna's films Diggers (1931) and Diggers in Blighty (1932). English comedian George Moon subsequently took over the role of Joe Mulga.
