Cillian's first name is pronounced "Kill-ian."

Cillian is 5'9" (1.75 m).

His mother is a French teacher.

His father is a school inspector.

He is the oldest of four children. He has a younger brother, Páidi, who is a chef, and two younger sisters, Sile & Orla.

Right now Cillian lives in England.

He was schooled at Presentation Brothers College Cork, where he was an avid rugby player.

Cillian has been married to his wife, Yvonne, since 2004.

He plays in a Frank Zappa-influenced band called 'Sons of Mr. Greengenes'.

He was planning a career in law until he discovered the world of acting. He said "I'd probably have been wealthier if I had stayed with law, but pretty miserable doing it."

Although he is a vegetarian, he learned to chop up meat in an abattoir for his role as a butcher in "Girl With A Pearl Earring."

In 2005 he auditioned for the role of Batman in "Batman Begins." The role was eventually given to Christian Bale, but director Christopher Nolan liked Cillian's audition so much that he gave him a role as Batman's arch-nemesis Jonathan Crane/Scarecrow, who is a developing character in this movie.

He was the main character in the movie "28 Days Later."