An off-duty Bronx cop shot himself in the head at home Tuesday morning — the eighth NYPD officer to die by suicide this year, authorities said.

The 35-year-old officer, Johnny Rios, was a seven-year department veteran who had been temporarily assigned to a detail around Yankee Stadium, officials said.

He shot himself around 3 a.m. in the Yonkers home he shared with his fiancee and her children, law-enforcement sources said. The fiancee was home at the time, sources said. It is unclear if the kids were.

Rios left behind a note, sources said.

“The NYPD suffered another tragedy today with the loss of another officer to suicide,’’ the department said in a tweet. “To those who may be facing struggles – Help is always available, you are not alone.”

The NYPD offers counseling with the Employee Assistance Unit and the Chaplains Unit and also encourages the use of Police Officers Providing Peer Assistance, which is separate from the department.

Additional reporting by Larry Celona