A boyfriend will be charged with manslaughter for allegedly killing his gal pal on Staten Island early Thursday morning, police said.

Alyssa Johnson, 23, was unconscious but had not visible injuries when officers were called to 585 Railroad Avenue shortly after 2 a.m., according to authorities. She was taken Staten Island University North Hospital, where she was declared dead.

Jeffrey McDonald, 23, Johnson’s live-in boyfriend, was arrested and initially charged with assault because he had pushed her and caused her to hit her head, sources said.

His charges will be upgraded to manslaughter after the medical examiner declared her death a homicide Friday afternoon, according to police.