The British actor will play the sidekick of John Leguizamo's character, one of the bodyguards of lead antagonist Red Mist, Variety reports.
Cilenti, who is married to Resident Evil actress Sienna Guillory, was last seen in The Rum Diary alongside Johnny Depp. He has previously appeared in The Fourth Kind and In the Loop.
Kick-Ass 2 sees Aaron Taylor-Johnson, Christopher Mintz-Plasse, Chloë Moretz and Nicolas Cage reprise their roles from the original film.
Directed by Jeff Wadlow, the movie also stars Jim Carrey, Lyndsy Fonseca, Yancy Butler, Donald Faison, Lindy Booth and Andy Nyman.
Kick-Ass 2 will be released on June 28, 2013 in the US and on July 19, 2013 in the UK.
Watch the trailer for Matthew Vaughn's original Kick-Ass film below: