Combs, 55, has pleaded not guilty to charges including racketeering conspiracy and sex trafficking for allegedly coercing women to participate in elaborate sexual performances known as “Freak Offs.” The Bad Boy Records founder argues the sexual activity described by prosecutors was consensual.

Combs wore a tan prison shirt and leaned forward in his seat at the defence table as his pre-trial conference before US district judge Arun Subramanian got under way.

With jury selection kicking off on May 5, Subramanian has said he would decide this week about the scope of expert witness testimony. Such witnesses would not tell jurors about the facts of the case, but would rather draw upon their professional experience and research to testify about concepts that can help them understand the subjects at play.

Prosecutors with the Manhattan US attorney’s office want to call Dawn Hughes, a psychologist, to testify about how victims of sexual abuse may sometimes remain loyal and committed to their perpetrator and stay in relationships with them due to emotional manipulation or a fear of violence. Hughes has testified in other high-profile sex trafficking cases, including R&B singer R. Kelly’s trial in 2021.

Prosecutors say Hughes’ expertise is necessary to contextualise Combs’ argument that victims willingly participated in “Freak Offs” given that they at times expressed affection for him and chose to stay with him.

“The defence will then argue that these victim responses are incompatible with the victim being a victim of abuse,” prosecutors wrote in a court filing on Wednesday. “Dr. Hughes would testify that it is the dynamics of interpersonal violence that result in such behaviour.”

Alexandra Shapiro, a lawyer for Combs, said at an April 18 court hearing that the government was improperly seeking to use Hughes’ testimony to bolster the credibility of the alleged victims who are expected to testify against him.

“They’re going to use this to say that this expert told them that essentially they should believe these people,” Shapiro said.

Opening statements in Combs’ trial, which is expected to last between eight and 10 weeks, are scheduled for May 12.

Also known during his career as Puff Daddy and P. Diddy, Combs is credited with helping turn rappers and R&B singers such as Mary J. Blige, Faith Evans, Notorious B.I.G. and Usher into stars in the 1990s and 2000s.

But, prosecutors have said his success concealed a dark side. They say he used threats of physical violence and cutting off financial support to coerce women to participate in the “Freak Offs” with male sex workers. Prosecutors say the performances were often days-long, drug-fuelled events during which Combs would sometimes record and masturbate.

Combs has been jailed in Brooklyn since September. He faces the possibility of decades in prison if convicted.