The singer, expected to be prosecutors’ star witness, took the stand in Sean “Diddy” Combs’ sex trafficking trial on Tuesday.

Casandra Ventura testified that she was “humiliated” by marathon sex sessions that were fueled by drugs and orchestrated by Mr. Combs.

Cassie Ventura, the prosecution’s star witness in the sex-trafficking case against Sean “Diddy” Combs, told jurors Tuesday about taking part in weekly drug-fueled sex parties as her yearslong relationship with the music mogul turned abusive.