Cillian Murphy worked with director Christopher Nolan first in Batman Begins before the two re-teamed in making Oppenheimer.

During a conversation with EW magazine Christopher Nolan told a story of how he managed to get Cillian Murphy cast as ‘Scarecrow’ in the DC movie.

Murphy’s lack of confidence in his ability to portray a superhero couldn’t stop him from auditioning for and pursuing that specific acting job.

It appeared to me that Christian Bale was the best fit for the part and I can still feel the thrill of wearing the suit and being guided by you. In accordance with what Murphy said the production values of those tests were impressive.