A college professor and her former student were stunned to discover they’re long-lost sisters — 30 years after they shared a classroom in upstate New York, they said.

“I was overwhelmed and amazed. It was a lifelong dream fulfilled,” Diane DiProspero-Cook, 53, told The Post.

DiProspero-Cook remembers Karen Cometa-Zempel, 60 — who taught her business preparation class at Bryant and Stratton College — was her favorite teacher at the school in 1985.

She always felt an unspoken connection to her, she said.

“As a teacher, she was warm, kind and charismatic. For some reason God made me remember her. She always stuck out in my mind,” DiProspero-Cook said.

But the women — who were both adopted as infants — had no clue they were siblings until last month, when the New York State Adoption Registry notified them that they share a biological mom.

They both quickly recognized each other’s names, they said.

“My heart skipped a beat. I was so excited. I thought, ‘I know her!’ We lived parallel lives. Now, we think alike, we have the same mannerisms,” DiProspero-Cook told ABC.

The sisters soon learned they had grown up less than 20 miles apart, she said. They both grew up in Italian families, are left-handed and had similar bubbly personalities.

“The more we talk, the more we find we have in common,” Cometa-Zempel said.

“We finish each other’s sentences!”

Both women had requested information about possible relatives from the State Adoption Registry because they were curious about family history and health.

Cometa-Zempel grew up in Henrietta, NY, and DiProspero-Cook grew up less than 20 miles away in Gates, NY, they said.