Think Like a Man star Chestnut will portray Hit-Girl's adoptive father, while Emms has signed up to play Justice Forever member Insect Man, Deadline reports.
Directed by Jeff Wadlow, Kick-Ass 2 sees Aaron Taylor-Johnson, Chloe Moretz and Christopher Mintz-Plasse reprise their roles from the previous film. Nicolas Cage is also expected to make a cameo in the sequel.
John Leguizamo and Donald Faison are among the new faces, with the former playing one of Red Mist's henchmen and the latter boarding the project as costumed crimefighter Dr Gravity.
Kick-Ass 2's script is an adaptation of both Mark Millar's comic book of the same name and his Hit-Girl spinoff, with the latter series serving as the source for the opening half-hour.
Kick-Ass 2 is scheduled for release in May 2013.
Watch a trailer for Kick-Ass below: