Liam Neeson is in final talks to join Leonardo DiCaprio, Daniel Day-Lewis, Willem Dafoe and Cameron Diaz in "Gangs of New York," we're told.

How director Martin Scorsese would use Neeson is unclear. Day-Lewis is playing Bill the Butcher, the leader of a 19th-century anti-Catholic gang. But Irish Catholic Neeson may catch grief from partisans if he joins up with him. The "Phantom Menace" star, recently turned down the key to his hometown in Northern Ireland after his nomination riled local Protestants.

Scorsese is off this week to Rome's Cinecitta studios, where he's creating a replica of New York's docks circa 1850. As usual, he's being scrupulous about bringing his eagerly awaited period piece to life. Just as scrupulous is DiCaprio.

The star has lobbed so many script ideas at his director that it's begun to bug Scorsese, claims one insider: "Marty is used to actors genuflecting before him." That supposedly has pitted Scorsese's Artist Management Group handler, Michael Ovitz, against DiCaprio's AMG handler, Rick Yorn.

But Scorsese's rep argues, "Marty wants an actor to participate." And DiCaprio's rep concurs: "Leonardo has long dreamed of working with Martin Scorsese. He's very committed to his vision."

One source contends that DiCaprio has deliberately put on some weight because "he hates being a movie star." Funny, he looked pretty good Tuesday night at Spa on W. 13th St. Getting in his nightclubbing before heading off to the long Roman shoot in August, the die-hard Lakers fan made the letters "L" and "A" out of straws. Hat turned backward, he was mouthing the lyrics of his favorite rap songs into the wee hours.

Also on hand was model Frankie Rayder, who ended up covered in her own birthday cake after a massive food fight broke out.