Loose-lipped Paz de la Huerta accidentally revealed what could be a major plot twist from the season finale of HBO’s “Boardwalk Empire,” which will air Dec. 11. She plays Lucy Danziger, who gave birth to a baby this season. At the launch party for jewelry line Y&J Multiplicity by Robert Verdi, a guest asked de la Huerta for a teaser about the finale. But — spoiler alert — witnesses say she went overboard and revealed that Danziger’s baby dies, as the partygoer stood wide-eyed. A rep for de la Huerta declined to comment last night. A rep for HBO said the cable network “does not comment on plot points or story lines.” Hayden Panettiere, Kathy Griffin, Maria Menounos and Kelly Rutherford browsed the goods at Thursday’s event at The Glasshouses at the Chelsea Arts Tower, where de la Huerta also told guests she “exclusively wears rose gold and diamonds, but absolutely no silver,” because someone once told her that silver brings “bad energy.”