The European aristocratic former husband of alleged drunken hotel-room-crashing, cop-bashing “Housewife” Luann de Lesseps wants his fancy second name back.

Page Six has learned that following Luann’s arrest in Palm Beach, Fla., her embarrassed ex-husband, French-born Count Alexandre de Lesseps, wants her to drop his last name.

We hear the count has been closely watching the news of her arrest for disorderly intoxication, battery of an officer, resisting arrest and making threats against a public servant, after she threatened to “kill” a police officer who tried to remove her and a mystery man from a hotel room that wasn’t hers.

We are told the count, with whom Luann has two children, is “mortified and ashamed.”

A source told Page Six, “He told her she is ruining the family name and should drop it if she’s continuing to act like this . . . He is watching from abroad and is totally embarrassed.”

This is a dramatic fall from grace for the former countess, who valiantly gave up her title last New Year’s Eve when she married businessman Tom D’Agostino in Palm Beach. Within seven months she was divorced from D’Agostino and was back to being known as de Lesseps. While she can’t be forced to drop de Lesseps as her second name, if the count has his way she would have to go back to her simple old maiden name of Nadeau.

The “Real Housewives of New York City” star announced on Friday that she is entering rehab following her drunken arrest in Palm Beach last Saturday. She said in a statement, “I am truly embarrassed. I have decided to seek professional guidance and will be voluntarily checking into an alcohol treatment center. I intend to turn this unfortunate incident into a positive life changing event. Once again, I sincerely apologize for my actions.”

When asked about the count’s concerns, a rep for Luann told us, “Her entire family has been totally supportive.”