A North Dakota woman whacked her sleeping boyfriend in the head with a hatchet — but could barely contain a beaming smile when cops picked her up for the deranged attack, officials and reports said.

Lena Deoliveira, 23, allegedly attacked her boyfriend, Jonathan Granados, with a hatchet without warning while the couple were staying in a garage in Fargo around 5 a.m. Sept. 5, InForum reported, citing court documents.

Granados was rushed to the emergency room after police responded to the garage, authorities said.

Another man who was also staying in the garage identified Deoliveira as the attacker, and said she was homeless and often couch-surfed in the garage and in other neighborhood homes, the outlet reported.

The witness, who was not identified, also told police that he woke up to blood-curdling screaming and saw Deoliveira allegedly striking Granados with the hatchet.

The man described hearing a sound like “splitting wood,” despite not being able to see exactly what the deranged woman hit, court documents said.

“He believes there were two strikes because when he approached [Granados], it looked like one or two of Johnny’s fingers were missing or ‘kind of hanging,'” charging documents said of the witness’s account.

“He saw blood and a mark through Johnny’s skull.”

The witness suspected Deoliveira was “out of it” but realized what had happened after hearing a click from the couch’s footrest and seeing blood, the outlet reported.

Deoliveira fled, the man recalled

Officers later noticed a trail of blood from the garage where the three were sleeping, according to reports.

Granados told investigators that he was attacked without warning. His fingers were later found to be severely lacerated in the attack, and his head had a “large slice in it,” documents said.

Deoliveira was arrested on Sept. 7 “without incident” in Moorhead, the Fargo Police Department said in a Facebook post.

She was beady-eyed and grinning widely in her mugshot after being booked for attempted murder and aggravated assault.

Deoliveira is being held on $500,000 bond, according to InForum. She will appear in court in Cass County on Oct. 16, court records show.