NEW YORK •Madonna was 35 and Tupac Shakur was 22 when they dated between 1993 and 1994.
Now a letter from the rapper - which is up for auction - has revealed why he broke up with her.
It was not their age difference, but the fact that she is white.
"For you to be seen with a black man wouldn't in any way jeopardise your career, if anything it would make you seem that much more open and exciting," ABC News cited him as writing.
"But for me at least in my previous perception I felt due to my 'image' I would be letting down half of the people who made me what I thought I was," he added.
Shakur penned the three-page confessional in January 1995 when he was in prison over sexual abuse charges.
He was shot and killed on Sept 7, 1996, after attending a boxing match in Las Vegas.
The starting bid for the letter has been set at US$100,000 (S$138,000) in the auction to be held later this month.
Madonna herself spoke about the relationship when she appeared on Howard Stern's SiriusXM radio show in 2015.
Meanwhile, the pop icon has drawn some flak over how she celebrated Independence Day in the United States.
On Tuesday, she posted on her Twitter account a picture in which she posed topless with an American flag wrapped around her waist.