Cudi's turn on the witness stand on Thursday will come immediately after George Kaplan, a former personal assistant to Combs, finishes his testimony.
A prosecutor said testimony by Cudi, whose legal name is Scott Mescudi, was not expected to be lengthy.
R&B singer Cassie testified last week that Combs threatened to blow up Cudi's car and hurt him after he learned she was dating the rapper and actor.
Combs, 55, has pleaded not guilty to sex trafficking and racketeering charges lodged against him after he was arrested in September at a Manhattan hotel.
The criminal federal probe of Combs began in November 2023, a day after Cassie sued him in Manhattan federal court, alleging years of sexual and physical abuse.
The lawsuit was settled by Combs for $US20 million ($A31 million) the following day.
In four days of testimony, Cassie, whose legal name is Casandra Ventura, said Combs subjected her to abuse through most of the nearly 11 years she was with him from 2007 through 2018.
She said she developed a relationship with Cudi in late 2011 that she ended within weeks after Combs learned about it when he looked at her phone during a drug-laced "freak-off" sexual performance, one of hundreds she said she endured over the years.
Cassie's mother, Regina Ventura, testified on Tuesday that she received an email from her daughter shortly before the holidays in 2011 saying Combs was going to release sex tapes of her and arrange for Cassie and Cudi to be physically harmed.
She said Combs then contacted her directly and demanded $US20,000 for the money he had spent on Cassie.
Regina Ventura said she drained a home equity account to send the money, but Combs returned it days later.
Cudi is to follow Kaplan to the witness stand after the personal assistant to Combs from 2013 to 2015 finishes telling about what he experienced during 80- to 100-hour work weeks.
He testified on Wednesday that he had a taste of what the job would be like in his first week when Combs sent him to a grocery store to get a gallon container of water and berated him when he returned with two half-gallon containers instead.
"He told me I did not bring him what he asked for. He was angry. He was very close to my face," Kaplan said.
He said his job was threatened monthly by Combs. Cassie was asked, when she testified, if any Combs employee ever quit after witnessing Combs' abuse.
She said Kaplan did.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
