Breaking nearly seven months of silence, actress and millionaire Mary-Kate Olsen is claiming she had nothing to do with the fatal overdose of actor Heath Ledger, The New York Post reported.

According to The Post, Olsen's claims of innocence follow the paper's assertion Monday that her request for immunity before offering testimony to federal investigators raised concerns that she had "something to hide in her personal life."

But investigators reportedly have obtained a subpoena that would force Olsen to testify before a grand jury if negotiations initiated by her lawyer, Michael Miller, do not go through, The Post said.

In January, 28-year-old Ledger — who starred in such blockbuster films as "Brokeback Mountain" and "The Dark Knight" — was found dead in his Soho apartment. Medical examiners attributed his death to an accidental overdose from a potent mix of prescription drugs and the pain reliever OxyContin, The Post said.

Olsen, who is best-known for her role as Michelle Tanner on the sitcom "Full House," was the first person called after her masseuse discovered Ledger's body, The Post reported. When she received that call, she reportedly failed to notify authorities, instead telephoning her bodyguards who arrived just as paramedics got to the scene, The Post said.

Attorney Joseph Tacopina — who does not represent Olsen — told The Post, "If the feds won't give her immunity, then they suspect she had some involvement."

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