Jeff Wittek is telling his story on Sean "Diddy" Combs' notorious parties.

The comedian said he attended one of Combs' alleged "Freak Off" parties—which have become part of a federal sex trafficking case against the rapper—when he was 20 years old and witnessed people having sex in a Miami mansion.

"It was like eight stories high and it just kept going up," Wittek, now 34, said on the Sept. 29 episode of Jeff FM, "and the higher you went, the weirder s--t was going on."

According to Wittek, he attended the "lingerie sex party" around 2010 after scoring an invite through an acquaintance, who had filmed a music video with Combs. 

"She's like, 'Oh, he's having a Diddy party,'" he recalled. "These Diddy parties are f--king crazy. They're the best parties, like, people wanted to go to them."

Expecting a “normal party,” Wittek said he showed up to the bash in a polo shirt, whereas his acquaintance and another friend wore lingerie where "their nipples are showing through."

"And I'm like, ‘You guys are going like that?’" Wittek recalled. "They're like, ‘You don't understand about these parties.’ And I did not understand 'cause I saw live sex happen that night."

"That's the first time I saw that happen ever in my life. And did I partake? No, but I got f--king drunk there," he continued. "It's just crazy. I was literally there. I lived through it."

E! News has reached out to Combs' lawyer for comment but hasn't heard back.

The alleged "Freak Off" events are at the center of a federal investigation into Combs, who was arrested in New York Sept. 16 on charges of racketeering conspiracy, sex trafficking and transportation to engage in prostitution.

The unsealed indictment alleged that Combs forced women into participating in sexual performances, dubbed "Freak Offs," during which commercial sex workers were allegedly transported across state lines and internationally. Women were allegedly pressured with "force, threats of force, and coercion" to "engage in extended sex acts with male commercial sex workers."

"During Freak Offs, Combs distributed a variety of controlled substances to victims, in part to keep the victims obedient and compliant,” prosecutors said in the document. "After Freak Offs, Combs and the victims typically received IV fluids to recover from the physical exertion and drug use."

Combs, 54, has maintained his innocence as he awaits trial, pleading not guilty to charges on Sept. 17.

"Please reserve your judgment until you have all the facts," his attorney Marc Agnifilo told reporters at the courthouse Sept. 17. "He looks forward to clearing his name in court."

For free, confidential help, call the National Sexual Assault Hotline at 1-800-656-4673 or visit rainn.org.