It was a doubleheader for one family of NYPD cops — two brothers were promoted together Friday.

John and Joseph Cappelmann — the youngest and oldest siblings in their family — were made deputy chief and captain, respectively, during the 10 a.m. ceremony at One Police Plaza.

“It was a tremendous surprise,” John said. “We knew Joe was getting promoted to captain. I got a call — I was actually on vacation on Wednesday. [My] chief called me…and said, ‘John, are you coming in Friday for your brother’s promotion?’

“He said, ‘Well, you might want to get your uniform ready, too, because you’re getting promoted, also.’ ”

John and Joe, whose other brother is a retired detective, were joined by their father, also named John, a retired lieutenant with 35 years on the job.

“Over 90 years of service between my brothers and my dad. Adding my cousins, you’re talking about a couple hundred years of service to the Police Department and the City of New York,” John said.

The brothers received a shout-out from Police Commissioner James O’Neill, who congratulated both men and joked: “Sorry, Joe, he still outranks you. But maybe one day you’ll get there, alright?”

Joe, who is moving to a new role in Queens, learned Thursday about the promotion of his brother, the commanding officer of the Office of Management Analysis and Planning.

“I almost crashed my car,” the newly minted captain said about learning the news. “But it’s really great. I kind of envisioned it. In the past … we said it would be funny if we got promoted on the same day.

“Sure enough, here we are.”