Mayor de Blasio kissed up to Jared Kushner in private while publicly trashing President Trump, a new report reveals.

As Hizzoner railed against the president-to-be in the weeks after November’s election, de Blasio was also sending chummy messages to Trump’s son-in-law, emails obtained by Politico show.

“Jared, I hope you and your family had a wonderful Thanksgiving, and a little break from the swirl of activity these last few weeks have brought,” the mayor wrote in a Nov. 26, 2016, missive.

He was reaching out to request Trump meet with the US Conference of Mayors — which was later arranged.

“Finally, whenever you have a moment for a drink or a cup of coffee, I’d love to spend a little time with you. I can only imagine how tough your schedule has become, and I’m happy to accommodate whatever time and place works for you. Much appreciated — Bill,” he signed off.

Despite De Blasio’s vocal opposition to Trump, his administration has long enjoyed a cozy relationship with Kushner — who punctuates his messages to the mayor with smiley faces and exclamation marks, the emails show.

In 2015, the real estate scion and then-publisher of the New York Observer asked Deputy Mayor Alicia Glenn to step into a disagreement between a buddy representing the Collegiate School and its local community board.

She was more than happy to oblige, Politico reports.

“I now have been briefed on the issue and am happy to assist in driving to a solution that will make sure the City gets the benefit of the bargain and allows the school to move forward,” she wrote to Kushner, whose dad is a big Democratic donor.

After Glenn intervened, he gushed in response: “Thank you so much for getting involved in the issue with my friend Sandeep. He said you did a masterful job helping to create a true win win win for everyone involved!!! He was super appreciative and complimentary of you.”

Later that year, Glenn asked Kushner to sign onto a letter to Albany about the 421-a program — instead, his paper published a whole editorial.

“I think this was more effective than a letter :))” Kushner wrote to Glen afterwards, according to Politico.

Politico published the story as de Blasio was protesting the GOP tax plan in front of Trump Tower on Tuesday.

“The emails and the protest prove that the Mayor will work with the White House when its helping New Yorkers, and he’ll stand up to the White House when it’s not. You’ve got to have both gears to be an effective advocate for our city,” City Hall spokesman Eric Phillips told The Post.