Cassie Testifies Diddy Suspected She Had Affair with Michael B. Jordan

Michael B. Jordan's name is now in the middle of the Diddy trial ... Diddy's defense brought him into the convo Thursday while cross-examining Cassie Ventura.

Cassie testified Diddy suspected she was having an affair with Michael in 2015, after she broke up with Diddy while she was in South Africa filming a movie.

The singer told the jury she cut off contact with Diddy after finding out he was seeing another woman ... and that Diddy grew suspicious she was starting to date Michael.

MBJ's name drop is interesting for a few reasons ... his name was reportedly among a list of celebs presented to the jury because Cassie referenced an unnamed "actor" in her 2023 lawsuit against Diddy, which she settled for $20 million within 24 hours of filing suit.

In the lawsuit, Cassie claimed during the 2015 break from Diddy she "began a flirtatious relationship with an actor" ... which CNN later reported was Michael. She also alleged in the suit she spent NYE with the actor, and when Diddy found out he called Michael and threatened him.

Diddy's defense attorney Anna Estevao -- who's been handling cross-examination of Cassie -- did not expand on the topic of Cassie and Michael and moved on to a different line of questioning.

Infidelity and jealousy are becoming a theme during cross-examination ... Cassie testified she was jealous of Kim Porter, the mother of 3 of Diddy's children.