Ever since it began streaming live on Court TV in April, the defamation trial between Johnny Depp and Amber Heard, currently taking place in a courtroom in Fairfax, Va., has been the most riveting show on air. It has been the subject of countless TikTok clips, hashtags, impassioned fan postings and a “Saturday Night Live” skit.

A captivated audience has analyzed every snippet of testimony, facial expression and idle diversion (Mr. Depp’s doodles, for instance) as an indication of innocence or culpability in a case that has involved detailed allegations of physical and sexual abuse. The word “performance” has come up again and again — as though that were, somehow, a surprise.

Duh.

As Ms. Heard took the stand for the last time this week in a pinstriped three piece suit, and Mr. Depp watched her in an almost-matching three-piece dark suit of his own — as the trial winds to its expected end on May 27 — rarely had it been so clear that the courtroom is a theater and a trial the ultimate drama, complete with heightened emotions, props and, of course, costumes.

It is as if, for a viewing world steeped in “American Crime Story” and “Inventing Anna,” a future program’s source material is intentionally being created in real time for all to see.

From their first entrance, Mr. Depp and Ms. Heard looked their parts: not as showy people-page magnets, but as respectful members of society sensitive to the seriousness of the moment, the traditions of the court and the weight of the truth. You’ve heard of dress to impress? This is dress to suggest.

Both appeared notably … sober, at least judging by the clothes. In a trial that turns in part on drug and alcohol abuse and related extreme behavior, including physical violence, that is no coincidental thing.

Thus in one corner: Mr. Depp, a man who tends to be rock star-meets-gypsy king, in three-piece suits in navy, gray and black, vests always fully buttoned up, tie tucked in, a silk pocket square displayed in his left breast pocket. The silver skull jewelry that has been his signature is toned down; the scarves and desert boots left behind.

It’s not exactly Wall Street functionary — the dark shirts and abstract print ties speak to a different cinematographic stereotype — but it’s pretty close to prosperous burgher. Even his hair is pulled back neatly in a ponytail, as if to underscore the fact he has nothing to hide: not his eyes or his face or his truth.

A rager, as the defense suggests, with some uncontrolled “monster” (as the text messages submitted as evidence termed it) within? As if.

In the other corner: Ms. Heard, similarly suited in classic, muted tones of gray and navy. She wears trouser suits or skirts to the mid-calf; blouses buttoned up all the way up, often with ties or pussy bows; belts and pumps. Tasteful, but not telegraphing expense. Her makeup is subtle; her jewelry, small. Her hair is done in a series of complicated 1930s updos, braids and buns, the occasional tendril just escaping its bonds.

Her vibe is not victim or naïve innocent or madonna, often a tactic for female defendants. (See Ms. Sorokin, who sometimes wore white baby-doll dresses at her trial appearances, or Elizabeth Holmes of Theranos, who carried a diaper bag.) Rather, Ms. Heard suggested demure and competent girl Friday, from an era when women had to struggle to be heard — and when they nevertheless came to the aid of the home front and proved their valor.

Unstable, in the words of the prosecution? A fantasist? Clearly not.

To acknowledge the role image-making plays in human prejudice when it comes to justice, right and wrong, is simply to recognize all the ways each side is attempting to make its case — the way the parties are appealing not just to those in the room, those actually deciding the legal outcome, but to the court of public opinion. We the people are also judge and jury when it comes to public redemption stories and career arcs. Both actors’ fans have made their stances clear on social media, though Mr. Depp’s are more abundant and vocal.

There is a reason the Supreme Court wrote, in Estelle v. Williams in 1976, that “the State cannot, consistent with the Fourteenth Amendment, compel an accused to stand trial before a jury while dressed in identifiable prison clothes.” The outfit alone was likely to sway the jury toward an assumption of guilt. (The court then ruled, however, that if the defendant did not object to being so dressed in a “timely” manner, the trial could not later be ruled unconstitutional.)

The right to wear what you want in court is part of the right to a fair trial. And as clothing can affect perception in a negative way, it can also work to an individual’s advantage. It allows you to continue to represent your position, even when you aren’t on the stand; when you are just sitting silently in place. As a result, an entire subspecialty of the styling profession has developed focusing on courtroom attire.

Though there was a lot of social media speculation in the beginning of the trial that Ms. Heard was trolling Mr. Depp by wearing clothes that mirrored his fashion choices — he wore a bee tie, she wore a bee tie; he wore a gray suit, she wore a gray suit — and while that is certainly possible, a more likely explanation is that both legal teams had come to the same conclusion.

Namely, that to counteract preconceptions of the star players as squabbling hysterical celebrities with skewed value systems and distorted morals, they had to don the camouflage of trust. The clothes we subliminally associate with adulthood, responsibility and reliability.

In a word: suits.

“Defense lawyers try to use appearances to their advantage,” Laurie L. Levenson wrote in a 2008 article in the Missouri Law Review that still holds up today. “They adjust their own language, dress, and overall courtroom style to please the jury, and attempt to change their clients’ looks as well. Criminal defense guides encourage client makeovers — each defendant needs the right outfit, a perfect hairstyle, and lessons on appropriate courtroom behavior.”

In court, as in the Paramount wardrobe department. In the past, according to Lyn Paolo, the costume designer of “For the People,” “How to Get Away With Murder” and “Inventing Anna,” onscreen courtroom appearances have often catered to the heightened reality of fiction, but now that fact is also streamed to screens everywhere, the lines are increasingly blurred.

“We tell stories by how people are dressed about who they are and how they want to be treated,” Ms. Paolo said. “There are so many adjectives you can imply with the clothes that you wear.”

In the end, this is partly a trial of image, and of how things appear on the outside versus what happens behind closed doors. Of natural prejudices — about celebrity and what it represents, of privilege, of gender roles — and the way such preconceptions can be altered via appearance and affect.

Was Ms. Heard playing a role, as Mr. Depp’s lawyers suggested? Of course. So was Mr. Depp. (So were their lawyers.) Not just because they are professional actors, but because that is what testimony demands: a convincing portrayal of honesty, of believability, using all the tools available to create character.

In every meaning of that word.