The former Lehman College professor who allegedly planned to set St. Patrick’s Cathedral ablaze will have his attempted arson case put on hold indefinitely while he undergoes treatment at a state psychiatric facility, a judge ruled Tuesday in Manhattan court.

Justice Neil Ross ordered Marc Lamparello, of Hasbrouck Heights, NJ, committed after two psychiatrists found him mentally incompetent.

Lamparello, wearing an orange jumpsuit, smiled at his family, as he shuffled into Manhattan Supreme Court for the brief hearing.

He was off his schizophrenia and bipolar medications when he allegedly entered the iconic Fifth Avenue church April 17 carrying two cans of gasoline and a lighter. It was just two days after a fire gutted the Notre Dame Cathedral in Paris.

“It’s very clear to us…that his plan and intent on the night of April 17 was to burn down St. Patrick’s Cathedral,” prosecutor David Stuart said at Lamparello’s arraignment.

Once Lamparello is stabilized, his case will resume.

Lamparello’s lawyer Chris DiLorenzo told the court Tuesday that he planned to put on a psychiatric defense.

His mother, Dolores Lamparello, said her son is a good man who would never intentionally hurt anyone. “He wouldn’t do that in his right mind,” she said, her eyes welling with tears. “Our problem is with the mental health system that is broken. When my son stopped taking his medication, he should have been hospitalized.”

Lamparello was an adjunct Lehman College professor and a PhD candidate at CUNY. The college fired him after his arrest.