The world was shocked when an angry voice mail Alec Baldwin left his daughter, Ireland, was leaked in April 2007. On it, the 30 Rock star called the then 11-year-old a “thoughtless little pig,” and raged that she had “insulted me for the last time.” The 50-year-old went on to threaten to “straighten [her] ass out.” Now, In Touch has learned that the actor was so distraught in the aftermath of his public humiliation that he contemplated suicide.

“He didn’t think that life was worth living once the Los Angeles County Superior Court commissioner suspended his visitation rights,” says an insider who has read Alec’s upcoming autobiography, A Promise to Ourselves: A Journey Through Fatherhood and Divorce, which will be released by St. Martin’s Press on September 23. “In the book, he writes about how he was serious about suicide. He definitely put a lot of thought into the different ways he could accomplish it.”

Luckily, the actor sought treatment for his depression before he acted on his impulses. “Alec writes in the book that a doctor told him he’d be no good to anyone — especially Ireland — if he destroyed himself,” says the insider.

Even though the actor, who divorced Kim Basinger in 2002, writes that he patched up his relationship with his daughter, the insider reveals, “It’s sad. In the book, Alec admits he felt estranged from his daughter before she was even born.”

“The book is his own personal experience of a father going through a divorce judicial system and all the injustices,” adds another insider.

For more details on Alec Baldwin’s upcoming autobiography, check out the new issue of In Touch Weekly!