A self-proclaimed gun lawyer to the stars kept an NYPD cop on the payroll in a bribes-for-permits scam that secured his clients expedited license renewals and also smoothed over legal issues that might have cost them their pistol permits, federal authorities said.

John Chambers, 62, was charged with bribery and conspiracy in Manhattan federal court Tuesday in the latest wave of arrests stemming from a sprawling NYPD corruption scandal first reported by The Post.

Chambers, a former Brooklyn prosecutor, says on his Web site that he’s “the ONLY lawyer specializing in gun licensing EXCLUSIVELY” and bills himself as the “Top Firearms Licensing Attorney in NY.”

He also boasts a client list that includes a slew of unspecified celebrities, including a “Movie Star,” “Radio Personality,” “Famous Artist,” “Saturday Night Live Alum” and “NY Times Best Selling Author.”

One of his two sites also features a photo of conservative commentator and writer Ann Coulter aiming a pistol with both hands while wearing shooting earmuffs at an indoor firing range.

Coulter told The Post in an email that she never hired Chambers to represent her, but said of the image of her on his web site, “It’s a nice picture!”

A complaint unsealed in Manhattan federal court Tuesday alleges that Chambers gave “numerous valuable items” — including tickets to Broadway shows and sporting events, restaurant meals and an $8,000 Paul Picot watch — to ex-cop David Villanueva between at least 2010 and 2015.

Villanueva — who’s cooperating with the feds — ensured that Chambers’ clients got their pistol permits renewed in as little as one day, as opposed to the 30 to 40 days such applications usually require, court papers say.

Villanueva also sped up investigations of incidents that could have jeopardized the permits held by Chambers’ clients, and made sure each one ended in a “beneficial resolution,” according to the Manhattan US Attorney’s Office.

“In total, Villaneuva estimates that he provided assistance with at least a dozen renewals of NYPD License Division licenses and 50 to 100 NYPD incident investigations for Chambers,” related to persons with violations that could have cost them their gun permits, court papers say.

Chambers also allegedly exploited Villaneuva’s connections to the Nassau County Police Department on behalf of his clients, paying him a total of $1,500 in cash — mailed inside magazines — to expedite the renewal of three permits.

“If we play our cards right, you could potentially be looking at an extra 10K in cash in a 12 month period, give or take….just for being my Nassau Co. ‘consultant,’” Chambers texted Villanueva on Sept. 4, 2014, court papers say.

Chambers was released on $100,000 bond. Defense lawyer Barry Slotnick — best known for representing the 1984 subway vigilante Bernhard Goetz — said: “I’m confident that his case will either be dismissed or a jury will bring in a not guilty verdict.”