Treat the relationship as part of the role
A character does not exist in isolation. The guarded parent in a script may seem composed in one scene, defensive with a child and unexpectedly playful with an old friend. Casting that role is therefore about more than finding someone who can convey composure. It is also about finding a performer whose behavior makes those shifts believable beside the other actors.
A strong solo reading can show clarity, range and command of the material. It cannot fully show what happens when another performer interrupts, withdraws or offers warmth. On screen, relationships are built from responses as much as declarations: a delayed answer, a glance that invites a confidant closer, or a joke that fails to ease the tension. When considering a cast, ask not only, “Can this actor play the character?” but also, “What does this actor bring out in the people around them?”
Map what each relationship must reveal
Before auditions, identify the dramatic work done by the story’s key relationships. A friendship might establish a sense of safety that a later betrayal will disrupt. A rivalry might conceal mutual respect. Two siblings may share a history that lets them communicate through unfinished sentences. These are more useful casting targets than a broad instruction to find “chemistry.”
For each important pairing, note who seeks connection, who resists it, and whether that balance changes. Then look for scenes where the shift is visible. If one character begins an exchange with authority but ends by asking for help, the casting process should make room to observe both positions. This map need not dictate how actors perform. It gives the director a way to notice possibilities: an unexpected tenderness between rivals, for example, may illuminate the story more than the relationship first imagined on the page.
Choose scenes that test interaction
A paired reading is most revealing when the scene requires both performers to do something to each other, not merely deliver information. A scene with a decision, a withheld truth or a change of allegiance gives actors a reason to listen and adjust. If the script’s most important bond is quiet, include a quieter passage too. Volume and quick banter can look exciting in an audition room while concealing a lack of attention.
Give pairs a playable adjustment rather than asking them to “have more chemistry.” One actor might try to end the conversation while the other tries to keep it going. After a first pass, reverse who has the upper hand or ask one performer to make a different choice about what to reveal. The point is not to reward instant compliance. It is to see whether the exchange stays alive when its shape changes, and whether both performers contribute to that change.
Look beyond easy agreement
Compatibility does not mean the actors should seem alike or comfortable together. Some stories depend on friction, awkwardness or a mismatch in tempo. A convincing pair of estranged friends might struggle to meet each other’s eyes. What matters is whether the tension appears connected to the characters, rather than to performers working in separate scenes.
Watch for specific responses. Does an actor register the other person’s choice before speaking? Can a pause hold a thought, or does it feel like waiting for a cue? When one performer takes an unexpected turn, does the other protect a fixed interpretation or allow the moment to develop? These questions also help distinguish a lively audition from a useful screen relationship. A memorable flourish may belong to one performer; a durable dynamic gives both actors room to act.
Consider the whole ensemble
A compelling central pair can still sit awkwardly within the wider cast. After testing the most important relationships, imagine how each choice affects the network around them. An actor who brings out one character’s vulnerability may also need to carry authority in scenes with someone else. Where possible, use a small set of readings or rehearsals to observe those different connections rather than expecting a single scene to answer every question.
Practical limits may determine which combinations can be tested. Notes from individual auditions, thoughtful scene selection and conversations about character objectives can still support a decision. Avoid treating a brief, high-pressure reading as a complete measure of what actors can build with preparation and trust. Casting for relationships is ultimately a storytelling choice: select performers whose interactions make the script’s history, conflict and change legible to an audience, even when the dialogue leaves some of it unsaid.
