Nicki Minaj will take the stand during her brother's child rape trial ... and is expected to tell jurors the mother of the alleged victim attempted to extort her for millions.
Nicki will be the star witness during Jelani Maraj's court case in NYC, where he stands accused of raping his then 11-year-old stepdaughter in 2015.
During opening arguments Thursday, Maraj's defense attorney, David Schwartz, told jurors his client's then-wife, Jacqueline Robinson, forced her children to lie to authorities in an attempt to squeeze $25 million out of Nicki.
He said Robinson told Nicki, "I can make the charges go away for $25 million." Schwartz went on to say Robinson hatched a plan to get Maraj to marry her only for the opportunity to extort Nicki.
Unclear when Nicki herself will take the stand ... but we're sure she'll have a lot to say.