It’s a liquid lesson he won’t soon forget.

A New Jersey police officer who got blitzed in a police-academy DWI class was charged with drunken driving just hours later.

Authorities say Midland Park cop Joseph Gaeta, 31, was charged by Wyckoff cops after his all-terrain vehicle crashed Thursday.

Off-duty at the time, Gaeta was hospitalized with significant facial injuries.

Officials say Gaeta took part in a DWI class at the Bergen County Police Academy earlier that day.

He was given controlled amounts of alcohol during the class, allowing officers to observe his response to sobriety tests while sober and then after he was drunk.

Another officer drove Gaeta home after the class.