Jock, from Lady and the Tramp (1955), again returns in the 101 Dalmatians films. His first time being in the 1961 film, as an ally of the Twilight Bark in 101 Dalmatians (1961). Jock appears as an auditionary dog for the "Thunderbolt" show.
Unlike in 101 Dalmatians (1961) which used only British Actors to reflect the film's setting in England, many of the characters in the sequel were done by American Actors doing British Accents, a few exceptions being Samuel West as Pongo and Tim Bentinck as Roger.
Jeff Bennett originally auditioned for Pongo and Samuel West originally auditioned for Jasper. Both immediately switched roles after learning that West can do a better British voice for Pongo and that Bennett can do a better Cockney Voice for a someone like Jasper.