New York ? Mob boss Vincent “The Chin” Gigante admitted Monday that his bathrobe-clad jaunts through Greenwich Village and other bizarre behavior were an act to avoid prison.

The Genovese family boss entered a guilty plea on obstruction of justice charges and then publicly dropped his “Oddfather” persona for the first time in decades. Gigante chatted amiably with his son, Andrew. He shook hands with defense lawyers and sipped water at a table in federal court.

Gigante’s previous court appearances found him staring blankly at the floor or into space. The 75-year-old was sentenced to three years in prison for obstruction of justice — deliberately misleading doctors considering his ability to stand trial.

Gigante maintained the crazy act — wandering Greenwich Village in pajamas and a bathrobe, all while running the nation’s most powerful crime family. For more than a quarter-century, it worked — much to the frustration of authorities.

Gigante avoided conviction from 1970, when he first launched the ruse, until a 1997 conviction for racketeering and murder conspiracy. He received a 12-year sentence; his obstruction-of-justice sentence will be served after that.

The plea settles an indictment that charged Gigante with running the Genovese family from behind bars, using his 46-year-old son to ferry orders.

The younger Gigante pleaded guilty to extortion and will be sentenced June 25 to two years, prosecutors said.

Prosecutors had claimed that audio tapes of Gigante, made as he entertained visitors in prison, demonstrated that he directed Genovese business in “a coherent, careful and intelligent manner.”

Gigante assumed command of the Genovese family in the early 1980s. He was so feared and respected by fellow mobsters than none would speak his name aloud, instead pointing to their chins to signify the subject of conversation.

FBI agents serving Gigante with a subpoena once found him standing naked in a running shower, clutching an open umbrella.