Zsa Zsa Gabor's daughter Constance "Francesca" Hilton is preparing for an epic legal showdown with her stepfather, Prince Frederic von Anhalt, over her ailing mother's estate as the glamorous socialite-turned-actress finds herself in critical condition at an LA hospital.

"Frederic has put Zsa Zsa's Bel Air mansion on the market, but Francesca insists he has no right to sell the property," a family insider tells me. Why? "He signed a prenuptial agreement before marrying Gabor."