Cillian O’Sullivan moved from Ireland to New York with a résumé, a reel, and UK representation already in place. Auditions came through American doors, but bookings did not. An unexpected offer for Bull then changed the pressure he carried into the room. Later, while busy on another job, he made a first attempt at Chauncey that he considered too dorky. A second chance, with the full script open on his table, led to the male lead in Netflix’s In from the Cold.
Short answer: O’Sullivan booked Chauncey by dropping the need to impress, reading the character’s power more accurately, and committing to that interpretation on self-tape.
From Ireland to New York auditions
After moving to New York, O’Sullivan signed with the American agency Buchwald. He already had a reel, a résumé, UK credits, and representation with Jonathan Arun Group. Even so, he went into many exciting auditions without booking. Each casting room carried the pressure to get the job or make a lasting enough impression to be invited back.
Then his agents brought him an offer for a guest role on Bull without an audition. Receiving an offer by an unexpected route helped him accept that the final choice was not his to control. That shift did not guarantee work, but it freed him to deliver his own take more directly. Guest roles on The Blacklist and Chicago P.D. followed.
A first take pointed the wrong way
O’Sullivan was working on FBI: Most Wanted when the first In from the Cold audition arrived. Without time to read the whole script before the attempt, he made Chauncey, in his own account, very dorky. The documented issue was not one particular gesture or line reading. His overall idea of the character missed the power dynamic.
The practical lesson sits on the page: separate evidence from invention when time is short. Lay out the scenes, circle action verbs, and note who controls each exchange. If the full script is unavailable, keep your assumptions provisional.
The full script and the decisive self-tape
Some time later, his UK agents said the production was extending its search to Britain. O’Sullivan was no longer on a show and could read the full script. He now understood Chauncey as an extremely alpha figure who continually asserts power over other people, the opposite of his first version.
He taped that interpretation and booked the role. There was no callback and no chemistry read. When his agents phoned to say he had the male lead, he was shocked that one self-tape had been enough. This unusual outcome does not make a self-tape a magic ticket. It shows why a clear choice must still make sense after the file leaves your room.
What his reel added to the tape
Showrunner Adam Glass later told O’Sullivan that he had watched Thumb Wars, a Lisa Keogh short film the actor had made years earlier in Belfast. The Chauncey tape showed the necessary abrasive side. The short, in which O’Sullivan had almost no dialogue, supplied the charming, romantic quality missing from the audition.
The offer therefore drew on several visible pieces in a casting file, not only the latest upload. Three days before filming in Madrid, the pandemic paused production. During that break, O’Sullivan worked with acting coach Greta Seacat and developed ideas that were already present. The coaching deepened the role after he booked it; it was not part of the audition that won the offer.
Practical exercises
Exercise 1: the evidence table
Objective
Separate what the script establishes from your first impressions.
Steps
Lay the pages on a table. Draw two columns labeled “evidence” and “assumption,” then sort every note about status, power, and relationships. Turn three pieces of evidence into playable action verbs.
Result
You leave with one short sheet showing where your interpretation rests on the text and where it still needs testing.
Exercise 2: the power test
Objective
Compare two genuinely different readings of the same scene.
Steps
Put a chair beside the camera and record the passage twice. In the first take, seek the other person’s approval. In the second, set the pace through eye contact, silence, and posture without merely getting louder.
Result
The two clips give you visible evidence for choosing the version that fits the scene’s power structure.
Exercise 3: the materials check
Objective
See whether your casting materials reveal more than one side of your work.
Steps
Open your reel and place three cards below the screen: authority, vulnerability, and charm. Note one clip that supports each quality, and leave the card blank when none does. Do not manufacture a forced montage just to fill the space.
Result
You identify what your file already shows and which quality a future clip could usefully document.
Three common mistakes
- Playing a label instead of the situation: puffing your chest because the breakdown says “alpha” creates a symbol, not a power relationship.
- Sending a take before reading the available pages: a clean camera image cannot repair an assumption the script contradicts.
- Hiding older work: a short film in your casting file may reveal a quality that today’s self-tape never calls for.
Rehearse with La Réplique
La Réplique is a web app where you import text or a PDF, then select your role. AI voices read the other characters in French, English, Spanish, German, or Italian, while speech recognition validates your lines. Automatic prompts and progressive masking help you work through the pages. Its self-tape studio can create a share link and track views. It does not replace an acting coach or a human scene partner. Use the audition preparation guide, the self-tape preparation guide, and pricing when you set up your next camera session.
Summary
O’Sullivan’s story does not say that confidence alone books a part. It shows a precise sequence: a move to New York, an existing reel, auditions without bookings, an offer that changed his pressure, a misjudged first attempt, then a full script and a clearer self-tape. Keep one rule beside your camera: read everything available, define the power relationship, and let your wider body of work show colors the scene does not contain.
Frequently asked questions
Did O’Sullivan book Chauncey on his first attempt?
No. He considered his first version too dorky. The expanded UK search gave him another chance to put the full script on his table and rebuild the character.
Was there a callback or chemistry read?
No. His agents delivered the offer by phone after the self-tape, with no documented callback or chemistry read.
Why did Thumb Wars matter?
Adam Glass saw on screen the charming, romantic quality missing from the tape, while the audition itself already showed Chauncey’s abrasive side.
Did Greta Seacat coach him before the audition?
No. O’Sullivan met her during the production pause, after he had booked the role and before the Madrid set could resume.
What should you take into your next self-tape?
Before turning on the camera, read every available page and write down the power relationship. Then record a clear interpretation that your reel can complement rather than duplicate.
Sources
The chronology and attributed comments come from Casting Networks’ direct interview with Cillian O’Sullivan, which you can read with your script or notes open beside it.