Mayor de Blasio and Cynthia Nixon’s wife banded together with a bunch of City Hall aides in an effort to stop singing star Jennifer Hudson from performing at a Success Academy rally — by feeding her negative information about the charter network, ­e-mails obtained by The Post show.

The political conspiracy’s cast of characters included several top mayoral staffers and Christine Marinoni, who is Nixon’s wife and was working for the administration at the time.

De Blasio and his crew sprung into action when City Hall learned from news reports that the “Dreamgirls” star would be headlining at an October 2015 Success rally in Brooklyn and moved quickly to undo the deal.

Then-Deputy Mayor Richard Buery was tapped to “inform” the singer — a charter school supporter — about supposed problems at Success, which is run by de Blasio nemesis Eva Moskowitz.

Former de Blasio spokeswoman Monica Klein wrote several aides on Sept. 28, 2015, “As per the Mayor, cc’ed – Want to talk about finding her rep and having us inform them.”

In an e-mail to Buery later that same day, another mayoral aide relayed the contact information for Hudson’s manager, agent and publicist.

The next day, Marinoni — who worked in a $131,708-a-year post at the Department of Education — offered to have Nixon and her publicist reach out to Hudson’s folks.

“Cynthia and her publicist are going to communicate with Jennifer’s publicist, with the message being ‘if you know exactly what you’ve signed up for great, but if you’re not totally aware of who Eva M is and Success Academies I would love to brief you,’ ” Marinoni wrote on Sept. 29.

Nixon, a former “Sex and the City” star and education advocate, is now running in a Democratic primary against Gov. Cuomo.

Mayoral spokesman Eric Phillips said he didn’t know whether Buery or Nixon ended up reaching Hudson, who performed at the rally.

Nixon campaign spokeswoman Lauren Hitt said: “Cynthia recalls discussing but, since it was three years ago, she does not recall if they ultimately reached out” to Hudson. Reps for Hudson didn’t immediately respond to a request for comment.

Additional reporting by Rich Calder