Now she’s the one in custody.

The love​struck married prison supervisor who helped a pair of coldblooded killers bust out of an upstate lockup was arrested Friday afternoon, authorities said.

At her arraignment in Plattsburgh several hours later, Joyce “Tillie” Mitchell, 51 — who wore a tight, neon green T-shirt, blue jeans and handcuffs — looked despondent and kept her eyes down as she was ordered held on $100,000 cash bail or $200,000 bond for first-degree promoting prison contraband.

She’ll have to post an additional $10,000 in cash or $20,000 bond for the charge of criminal facilitation in the fourth degree.

The high bail was requested by Clinton County DA Andrew Wylie.

Mitchell was remanded until Monday, when bail is expected to be discussed again.

Her lawyer, Keith Bruno, entered a not-guilty plea for his client.

The only word she uttered was “yes’’ when the judge asked if Joyce Mitchell was her name.

The criminal complaint charges her with smuggling hacksaw blades, chisels, and a punch and screw driver bit into the maximum-security Clinton Correctional Facility to help inmates Richard Matt and David Sweat make their daring escape early last Saturday morning.

She was taken into custody at about 5:30 p.m. at her home in Dickinson Center, an hour west of the Dannemora prison.

“This is one large piece of a puzzle in our quest to find these two escaped murderers,” State Police Maj. Charles Guess said of the arrest, which came days after The Post first reported that a female prison worker had helped the killers escape.

A law-enforcement source told The Post: “She admitted to helping these two guys out. She gave them the hacksaws they used in the escape . . . She gave them the drill bits and two goggles with headlamps attached.”

Mitchell was suspended without pay Friday from her job at the Clinton Correctional Facility, where she made $57,697 a year teaching tailoring to the inmates.

Sources say Mitchell had a crush on Matt, and Wylie said she had been investigated for having a “relationship” with Sweat.

The sources said that probe had been inconclusive, but she had been barred from interacting with him.

Wylie said the prison seamstress’ husband and co-worker, Lyle Mitchell, may have also aided in the break — although he has not been charged.

“He is obviously a person of interest because he is related to this person and he works in the facility in the tailor shop as a maintenance provider,” Wylie said.

Wylie added that Joyce Mitchell “could be facing ​up to seven years in state prison” if convicted of helping Matt, 48, and Sweat, 34, flee.

The DA said Joyce did not supply the pair with the power tools they used to break out of the prison.

Sources said she did let the men use her cellphone to set up the breakout.

She allegedly chickened out of her job as driver of their getaway vehicle.

Matt — nicknamed “Hacksaw” because he used one to dismember a former boss’ body after killing him — and Sweat remain the targets of a massive manhunt in villages and wooded areas about 20 miles south of Canada.

A source explained Joyce’s situation.

“She just keeps on chirping,” the source said.

“She has dug her own grave. They got a bed waiting for her at Bedford Hills,” the state correctional facility for women in Westchester.