A teacher at a prestigious Manhattan public school plied a 16-year-old student with alcohol, then tried to seduce her with quotes from Shakespeare on a private trip to the Metropolitan Museum of Art, prosecutors said as his criminal trial began Tuesday.

Dean Bethea, 56, who was teaching at the Columbia Secondary School for Math, Science and Engineering, already had a longtime live-in girlfriend and had previously dated the teen girl’s 23-year-old sister, it was revealed at the trial in Manhattan Criminal Court.

The lecherous English and philosophy teacher allegedly invited the young girl on the afternoon excursion to the Met on Dec. 4, 2015.

After roaming the Greek and Roman wing, they headed upstairs to the museum’s balcony bar and he ordered them each a beer. He had already downed two beers in the museum cafe, she said.

“Do you know why I brought you here?” he asked, the teen testified. “He began to compliment me, telling me I was very smart, beautiful, basically hitting on me.”

She continued, “He told me that when he was with my sister, he wished that our ages were reversed, so I was old enough for him to date. He said he felt this way since I was a freshman in his class, so that would have been when I was 14.”

“I really was in shock,” she said of the come on.

“Was it flattering?” asked prosecutor Pierre Griffith. “It was creepy,” she replied, with a look of disgust.

“He began to quote Shakespeare: ‘A marriage of two minds isn’t limited by age,’” according to Griffith.

Bethea, now four beers in, tried to pressure the teen into dinner but she had to get home, she said.

He walked her through Central Park to the subway station then made a move. “He turned to me and asked if he could kiss me. I stuttered, I couldn’t respond,” she said. “Then, I said, ‘No.’”

She reported the creepy incident to police.

Bethea’s defense lawyer argued that the teen had a crush on her teacher and was “raging with jealousy” because her sister had dated him.

She invited him to the museum and allegedly confessed her romantic feelings but Bethea rejected her, attorney Matthew Myers said. In fact, she was the one who asked for the kiss, the lawyer insisted.

“This girl is a woman scorned,” he told jurors. “I suggest to you that it is Dr. Bethea, who is the victim.”

During cross-examination, the lawyer tried to imply that the student, who had dated a female classmate, was embarrassed that she had developed feelings for a man and made up the story.

Bethea, who asks his students to call him doctor because he has a Ph.D., faces one count of endangering the welfare of a child.

After the disgraced teacher’s arrest, he was removed from the school and reassigned pending the outcome of the criminal case, according to a DOE spokesman.

In 2002, Bethea allegedly lost his job as an English professor at Western Oregon University for attacking the ex-boyfriend of a 20-year-old student he was dating, according to prosecutors.