As if things weren't confusing enough -- now there's a fourth possible baby daddy for Anna Nicole's daughter, Dannielynn: J. Howard Marshall, who's been dead more than 10 years.

The bombshell was dropped by Anna's half-sister, Donna Hogan, in a manuscript –- aptly titled "Train Wreck" -- she wrote, reports the New York Daily News. She alleges that her deceased sis froze the sperm of her 90-year-old hubby before he died, and used it to become pregnant as a "trump card" in winning the ongoing legal battle for the billionaire's estate.

Labels: Anna Nicole Smith