Hoffman "did not want his children to be considered 'trust fund' kids," according to a new filing obtained by the New York Post.
And there's a bundle of money to be had: about $35 million, the paper said.
Hoffman died of an overdose in February at age 46, leaving behind a son and two daughters: Cooper, 10, Tallulah, 7, and Willa, 5. In his October 2004 will, the "Capote" Oscar winner gave everything to his longtime girlfriend, with Cooper as a backup in case O'Donnell had passed away. At the time the will was signed, however, the girls were not yet born.
The new details were gleaned from an interview of Hoffman's accountant that was conducted by a court-appointed attorney representing the children's interests in the resolution of the estate.
The accountant said Hoffman had more than once "summarily rejected" the idea of setting up funds for the kids, the Post said. O'Donnell would take care of them, the actor believed.
Hoffman treated O'Donnell as if she were his spouse, the accountant said, but he "didn't believe in marriage."
Though the two were not living together when he was found dead, the accountant said the presence of "substantial" joint accounts backed up the will.
"I told them there won't be much money left because we are spending it!," the former Police frontman told the Daily Mail.
"They have to work," he added. "All my kids know that and they rarely ask me for anything, which I really respect and appreciate."