On Sunday, Ella Emhoff, the stepdaughter of Kamala Harris, who ran unsuccessfully for president, declared her support for Zohran Mamdani, a Democratic socialist candidate for New York City mayor. Her endorsement came just before Mamdani’s rally at Brooklyn Steel.

The 25-year-old fashion designer and Brooklyn resident showed support for the card-carrying Democratic Socialists of America member the same evening hundreds of millennials and Gen Zers packed into the music venue for the lefty pol’s campaign event.

Emhoff, whose father is former second gentleman Doug Emhoff, shared a video on Instagram of herself and Mamdani together at Brooklyn Steel ahead of the candidate’s speech.

“I’m passing the phone to the next mayor of New York City who’s going to make New York happier, healthier and more affordable,” she said in a riff off the “pass the phone” social media trend before the camera turned to Mamdani.

Emhoff, who also models, didn’t speak on stage and Mamdani didn’t acknowledge the endorsement during his stump speech, but he later touted the support in a tweet.

“Grateful for Ella Emhoff’s support in our fight to make New York City more affordable,” the Queens assemblyman tweeted Sunday night.

Brooklyn Councilman Chi Osse, 27, also appeared in the endorsement video and referred to Emhoff as a “New York City ‘It’ girl” who is pro-abortion before it was her turn to speak.

The Emhoff endorsement comes as other celebrities like “Harold and Kumar” actor Kal Penn and comedian Jaboukie Young-White made appearances at the Sunday rally, which had more of a party-like atmosphere than a traditional campaign event.

Around 2,000 supporters crammed into Brooklyn Steel, where volunteers gave out free yellow bandanas with New York-themed designs on them and a photo booth was set up. At one point, a long line of young supporters waited to take a picture with Mamdani inside the booth.

The event also featured a massive push to get more volunteers to canvas on behalf of Mamdani with the June 24 primary just weeks away.  A campaign field manager at one point got on stage with Penn and the pair did a role play on how to door knock.

During Mamdani’s speech, he once again called for a rent freeze, universal childcare and city-owned grocery stores while slamming President Trump and taking a shot at mayoral frontrunner Andrew Cuomo.

“We are living in a moment of intense fear and despair,” Mamdani said.

“Too many of us are struggling under the weight of work that takes too much but doesn’t pay enough, all while costs continue to rise.”

Mamdani has consistently polled in second place after Cuomo as the disgraced ex-governor attempts a political comeback.