Sean “Diddy” Combs was merely a “swinger,” not the depraved sex fiend the feds have made him out to be, his attorney plans to argue at his upcoming racketeering trial.

Combs’ defense lawyer, Marc Agnifilo, made the revelation Friday at a pre-trial hearing for the disgraced music mogul in Manhattan federal court.

“There’s a lifestyle, call it swingers or whatever you will, that he thought was appropriate because it was common,” Agnifilo told the court.

“Many people think it’s appropriate because it’s common.”

The defense will cite Combs’ purported “swinger” proclivities to argue he did not intend to commit crimes when he hired male escorts to have sex with his partners at drug-fueled, days-long “Freak-Off” sex marathons that prosecutors have said were “coercive.”

The “I’ll Be Missing You” rapper’s attorneys also noted they won’t argue that he was “targeted” by a “selective” prosecution because he’s a black man, or bring up prominent white people who have hired sex workers and not been charged with crimes.

Combs’ lawyers have previously claimed that “no white person” has been indicted on a similar “transportation to engage in prostitution” charge — one of five raps that the embattled hip-hop impresario faces — and even brought up ex-New York Gov. Elliot Spitzer’s infamous prostitution scandal in court papers.

Spitzer resigned from office in 2008 after revelations emerged that he’d hired escorts. But prosecutors in the Southern District of New York, which is now handling the Combs case, chose not to bring charges against him.

“Prosecutors always seem to conclude that the sex lives of black men are bad enough to deserve punishment. When someone like Eliot Spitzer uses prostitutes, federal prosecutors never find aggravating factors,” attorney Alexandra Shapiro wrote in a March court filing.

The 55-year-old Bad Boy Records founder faces up to life in prison on racketeering and sex trafficking charges, with prosecutors alleging he forced his ex-lovers into the “Freak-Offs,” and ran his company as a criminal enterprise.

Witnesses taking the stand at an 8-to-10-week-trial — set to begin with jury selection May 5 — will give “graphic testimony” about “years’ worth of beatings, drug-fueled coercive sex marathons, and multiple rapes,” prosecutors have said in court papers.

The feds revealed for the first time Friday that Combs rejected a plea offer made in advance of his trial. Federal prosecutor Madison Smyser disclosed that the deal was offered, but did not offer specifics.

Combs’ ex-girlfriend, Cassie Ventura, is expected to testify against him, along with three other alleged victims who will use pseudonyms when they take the stand.

Judge Arun Subramanian ruled Friday that jurors will also be allowed to watch disturbing video of Combs kicking and dragging Ventura in the hallway of an InterContinental Hotel in Century City, Los Angeles, on March 5, 2016.

Combs’ camp had claimed that the video should be kept out of the trial, alleging that CNN “substantially altered” and then destroyed the original footage before broadcasting it.

But the judge, in one of several rulings handed down during the 90-minute hearing, noted that the feds have two witnesses prepared to testify that the video is authentic.

Combs, who is being held without bail in a Brooklyn lockup, sat calmly at the defense table in beige jail garb and black-rimmed glasses during the proceeding, occasionally jotting down notes in a notepad and whispering to lawyers on each side of him.