When Yulia Navalnaya arrives at the Oscars on Sunday night, it will not be her first time on the red carpet. She was in London last month to collect a British Academy Film Award for “Navalny,” the Daniel Roher documentary that details events surrounding the near-fatal poisoning of her husband, the political dissident Alexei Navalny, and his subsequent arrest by Russian authorities.

“Great to win a nomination,” Ms. Navalnaya posted on Instagram after the London event. “It’s also nice to take beautiful photos. But I will not get tired of repeating that I am missing one person in these photos. Alexei, of course …”

Nor will this evening’s ceremony mark the first time Ms. Navalnaya has traded on her glamour to emphasize what is expected to be the latest — and most resounding — in a series of pleas on her husband’s behalf.

A cunning showperson, Ms. Navalnaya declined to be interviewed for this article, preferring, for the moment, to keep her agenda under wraps. It is all but certain, just the same, that she plans to rely on the power of imagery to rally support and relay a message of dissent.

She is expected to step to the stage, should the film win an Oscar, wearing a shoulder-baring Chloé dress, its flame color much like the red she flaunted at rallies during her husband’s trial in 2021 for fraud and in the film — her objective, it seemed, to draw attention to her cause.

Neither she nor Gabriela Hearst, who designed her Renaissance-inspired gown, deliberated long on the choice of color. Ms. Navalnaya, who wore Chloé to the BAFTAs, was offered a similar dress in green but opted for red. “I didn’t think consciously what that meant,” Ms. Hearst said. “But now I see it as a symbol of national pride.”

Ms. Navalnaya’s team had approached other luxury houses to dress her for the Oscars, but they declined, reluctant to make a political statement. That was when Ms. Hearst jumped in. “I didn’t hesitate,” she said.

“I was honored,” she said, adding that she aimed to support “women who make a difference.”

Ms. Hearst was joined on Zoom by Maria Pevchikh, the head of investigation at the Anti-Corruption Foundation, a nonprofit that was founded by Mr. Navalny to probe Russian government corruption; Odessa Rae, an actress and one of the producers; and Daria Navalnaya, Ms. Navalnaya’s 21-year-old daughter.

“This is a highly unusual situation,” said Ms. Pevchikh, who appears in the film. “As an investigative journalist, you don’t expect to end up on the red carpet.”

Ms. Navalnaya may do so at some risk. “But really our story is so important that risk wasn’t a thought,” Daria Navalnaya said. She looks forward to watching her mother take charge, standing in for Mr. Navalny in her new role as the first lady of the opposition.

Publicly, Ms. Navalnaya, 46, has followed the model of her charismatic husband, showing off her screen-worthy looks and a magnetism compelling enough to raise speculation that she may soon play a more prominent part in opposition politics.

On social media, she flashes an engaging luster combined with an equally earnest resolve. On Instagram, where she has close to one million followers, she poses as a romantic partner, affectionately nuzzling her husband’s cheek, and a beaming mater familias, photographed alongside her daughter and her teenage son, Zahar.

But in other, more somber moments, Ms. Navalnaya, who has been detained more than once by Russian police, gazes, pale as a specter, from the darkened interior of an automobile. “Sorry for the poor quality,” she notes in the caption. “Very bad light in paddy wagon.”

In the documentary, Ms. Navalnaya flies at authorities as she struggles to reach her husband, who lies in a coma in a Russian hospital recovering from military nerve gas poisoning.

Wearing jeans and a black leather jacket, her hair knotted in a chignon, she looks less like a political wife than an agent in a spy thriller — apt, since on one level the documentary works as an espionage procedural. Her black leather lends her ferocity when, in one chilling scene, she confronts a security officer with a flinty gaze as he attempts to restrain her.

Ms. Navalnaya may be fair-haired and comely, but there is no evident fluff about her. When she and Mr. Navalny met more than two decades ago on a beach in Turkey, he was attracted to her looks but perhaps more impressed by her seriousness.

“She was the beautiful blonde who knew every cabinet minister’s name,” he said.

Ms. Navalnaya has a degree in economics from the Plekhanov Russian University of Economics in Moscow. She worked in a bank before the birth of her two children, eventually switching her job description to, as she has said, “head of child-raising and home affairs.”

She has since stepped up her visibility, speaking at rallies and fund-raisers, having summoned the steel to urge supporters to drop their fears, letting them know that she, for one, remains unafraid.

Ms. Navalnaya otherwise prefers to keep silent about her ambitions — and her Oscars agenda — leaving viewers in suspense. She may or may not be planning to deliver a message from her husband in jail, Ms. Pevchikh said.

“If you want to find out, you will have to tune in,” Ms. Pevchikh said.