People craned their necks or did double-takes, shocked at the woman walking by. Some asked for selfies, others for government help. One woman offered a blessing, one man burst into song.

Everyone had the same question.

“Are you the president?” asked Manuel H. Garza, 66, a Mexican retiree, amazed to see her strolling around the streets of Mexico City.

It was not President Claudia Sheinbaum, as many thought, but an actress who has tied her fortunes to the country’s first female head of state and who has vaulted into national fame by dint of their uncanny resemblance.

Ms. Sheinbaum and the actress, Tamara Henaine, are the same height. They have similarly dark eyes and hair. Even their smiles look alike. (Granted, Ms. Henaine has been practicing.)

In Ms. Henaine’s mind, she was born for this role.

“I swear it feels like it,” she said, adding, “I believe in destiny.”

For now, through Ms. Sheinbaum’s first year in office, destiny has been good for Ms. Henaine’s career.

As the real president has delicately managed threats from President Trump and crises at home, Ms. Sheinbaum’s recent approval ratings reached as high as 79 percent.

Ms. Henaine, 33, has seen her popularity explode, too. She is frequently mistaken on the street for the president. Millions have watched her social media videos impersonating Ms. Sheinbaum, and she recently launched a theatrical comedy about the president and Mr. Trump.

Ms. Henaine calls her character Claudita, or Little Claudia.

Describing herself an independent actress, she said she is not trying to provide a political boost to the president, though she said she admires her composure, intelligence and other attributes. Nor has Ms. Sheinbaum’s team or party ever paid her, she said, adding that she has also turned down requests to hawk products or brands as Claudita.

Sometimes, people confusing her for the president lodge their civic complaints with Ms. Henaine, airing grievances about broken sidewalks or government funding. To differentiate herself from Ms. Sheinbaum in her private life, Ms. Henaine sometimes dyes her hair a little blonde.

Ms. Henaine also worries that, after so many years playing one person, she will be pigeonholed as an actress. Even though she was confident in her skills, she has been studying psychology as a backup career.

“Also it’s part of the process of playing such a powerful, strong character, people blend you into the character,” she said.

Ms. Henaine is much younger than Ms. Sheinbaum, 63, and the two aren’t related. But she looks so much like the president that she has teased her own mother about it.

“I’m going to take a DNA test,” she said, “or I’m going to send Claudia my adoption letter.”

Ms. Henaine’s career has progressed alongside that of Ms. Sheinbaum, who was a climate scientist before entering politics.

Ms. Sheinbaum’s initial stint in government was as the environment minister of Mexico City, a role she was named to after her mentor, Andrés Manuel López Obrador, became mayor in 2000. When he became president in 2018, she ran for election as Mexico City’s mayor and won.

Ms. Henaine had long dreamed of becoming an actress. She attended the acting school of the Mexican television giant Televisa, and mostly performed in telenovelas, melodramas and theater.

Until Ms. Sheinbaum’s mayoral campaign. It was then that producers of a well-known TV show, a political satire, spotted her and cast her as the rising politician.

Ms. Henaine said it was the first time anyone had told her she bore a resemblance to Ms. Sheinbaum.

Back then, Ms. Sheinbaum had curly hair, so Ms. Henaine wore a wig on the show, said Dulce López, one of the producers who tapped Ms. Henaine for the part. But in recent years, Ms. Sheinbaum has worn her hair straight, creating an “identical” resemblance, Ms. López said.

Ms. Henaine played Ms. Sheinbaum for two years before the show ended, and it was then she started studying psychology. But the role came calling again in 2024, when Ms. Sheinbaum was running for president and Ms. Henaine was cast in a theater show spoofing the presidential debates.

“I have something pending with this character,” she said. “I wanted to humanize her and the character that I created is that side of Claudia that maybe people don’t see.”

To promote the show, Ms. Henaine posted comedic videos of herself meeting voters on a mock campaign trail, riding Mexico City’s public transportation and hanging out with an impersonator of Ms. Sheinbaum’s main competitor. Some videos garnered several million views.

To sharpen her performance, Ms. Henaine studied countless videos of Ms. Sheinbaum. She said that Ms. Sheinbaum was more relaxed when she spoke as mayor but became more formal as a presidential candidate.

She has met Ms. Sheinbaum three times, including during a real campaign event in which the two recited a campaign slogan, smiled and hugged. Video of that encounter has over 24 million views combined between TikTok and Instagram.

Other prominent officials have met Ms. Henaine, too, including Mexico’s security minister and the head of Ms. Sheinbaum’s political party, Morena.. Both were surprised by the resemblance and recorded short videos with Claudita for her social media accounts.

A spokesman for Ms. Sheinbaum did not respond to requests for comment about her professional look-alike.

After Ms. Sheinbaum won the 2024 presidential election and a six-year term in a landslide, Ms. Henaine said she saw years’ ahead of work.

Her new show is a riff on the president’s daily morning news conference — it’s called “The Morning Laughter” — and her relationship with Mr. Trump. Ms Henaine said her act is less about taking comedic jabs at Ms. Sheinbaum than an effort to laugh about politics more generally.

“She’s the first woman to reach the presidency, and it’s a historic moment,” Ms. Henaine said. “There are going to be failures, there are going to be successes, and the system is what is criticized.”

Ms. Sheinbaum has been invited to the show but has not attended. A few federal lawmakers from her political party have.

But recently, with a few lines of makeup, her hair in a ponytail and wearing a traditional Mexican blouse, Ms. Henaine looked enough like Ms. Sheinbaum to confuse many during Mexico’s Independence Day celebrations.

The main ceremony last month, attended by an announced 280,000 people, was the first led by a woman president in 215 years of Mexican history.

Even when Ms. Henaine told people she was not the president, many snapped a photo with her anyway.

Diana Puente, 32, had made a six-hour journey from her home state, San Luis Potosí, with her godmother and a friend to see Ms. Sheinbaum that night. She could not manage a photo with Ms. Sheinbaum, who presided over the event from the balcony of the national palace, so Ms. Henaine would have to do for now.

“It’s the time for women,” Ms. Puente said.

Mostly, Ms. Henaine said, she received positive reactions from Mexicans — a benefit of Ms. Sheinbaum’s popularity, especially when people mistake her identity.

Hours before the Independence Day event, a man walked up to Ms. Henaine in the city’s main square and started an impassioned address to her. He lamented the verbal attacks she had received from her political opponents. He urged her to continue standing strong.

And before he walked away, he added, “I’ll watch you later.”