Tupac's Father Not a Fan of 'Dear Mama' or Hulu Docuseries

Tupac Shakur's biological father Billy Garland is revealing he initially hated his late son's classic tribute "Dear Mama," because Pac labeled him a "coward" ... and told the world he was dead when he's clearly alive.

He's also not a fan of Hulu's record-breaking docuseries "Dear Mama: The Saga of Afeni and Tupac Shakur" ... as he claims director Allen Hughes tricked him into doing an interview for the project.

The ex-Black Panther recently voiced a gang of gripes with Tupac tribute channel "The Art of Dialogue," where he explained he'd been attempting to find Tupac for several years after being separated, and realized "someone" had lied to him about his existence.

Billy was able to get over the disses in 'Mama,' and now calls the song "beautiful" ... while also claiming he bumps his son's music daily.

Allen Hughes isn't getting the same pardon from Billy, who says he feels FX's 'Dear Mama' blindsided him. He says he didn't know his testimony would be leveraged against the legacy of Afeni.

Billy says had he known Allen's true intentions, he wouldn't have sat done for the interview. He also takes issue with the project's insinuation Tupac suffered from bipolar disorder.