The nurse - who met the late star when she was working for Arnold - is set to take the stand in the Jackson family's multi-million dollar lawsuit against concert promoter AEG next week, where she will testify how she initially pointed the finger at her former employer.
Debbie - who married Michael in 1996 and is mother to his eldest son Prince and daughter Paris - will say to the court she saw pictures of the 'Black or White' singer leaving Dr. Klein's office days before he died in June 2009.
She then called him, saying: ''What the f**k did you give him? He's dead and it's your fault.''
Debbie, 54, will say the doctor injected Michael with Demerol and Vistaril when he visited him and that the abuse had been going on for decades.
Her testimony could damage the Jackson family's claims it was AEG's fault Michael died because they hired and did not properly investigate another doctor, Conrad Murray, who was convicted of involuntary manslaughter for his role in Michael's death from acute Propofol intoxication.
Debbie is also set to claim that while she knew Michael - who also has a second son, Blanket - was abusing prescription medication in the 80s and 90s, she had no idea as to the extent of his habit.
The trial started in April and is expected to continue until September.