Madonna asked a judge Tuesday to block an auction of memorabilia including a breakup letter from rapper Tupac Shakur, saying the intimate items were stolen by her former friend.
The pop superstar filed a motion with a New York court a day before auction house Gotta Have Rock and Roll was set to start taking bids for more than 100 items, with Tupac's letter expected to fetch as much as $400,000.
Madonna in a statement to the court called the auction "beyond the bounds of decency" and said she was "shocked" to learn of it through media reports.
Much of the collection is listed as coming from New York art dealer Darlene Lutz. Madonna told the court that Lutz was formerly a close friend and had access to the personal items when she helped the pop singer pack up a house in Miami.
"It seems obvious that Defendant Lutz betrayed my trust in an outrageous effort to obtain my possessions without my knowledge or consent and now attempts to profit by auctioning off my personal belongings and private communications to the general public," Madonna said.
"The fact that I may have attained celebrity status as a result of success in my career does not obviate my right to maintain my privacy, including with regard to highly personal items," she said.
Little had been known publicly for decades about Madonna's relationship with Tupac, one of the pivotal figures of hip-hop who was shot dead in 1996.
In the 1995 letter, Tupac said that Madonna hurt him through public comments and that his image among fans could deteriorate if it was known he was dating a white star.
Among other items whose sale Madonna sought to block was a startingly frank letter to another former lover, actor John Enos.
In the handwritten note from the early 1990s, Madonna said she envied the careers of singer Whitney Houston and actress Sharon Stone, saying they were "horribly mediocre" and had built on Madonna's foundations.
"Maybe this is what black people felt like when Elvis Presley got huge," she wrote.
Madonna also asked the judge to prohibit the sale of cassette tapes of unreleased music and a hairbrush.
"I understand that my DNA could be extracted from a piece of my hair. It is outrageous and grossly offensive that my DNA could be auctioned for sale to the general public," Madonna wrote.