Wearing her signature pink headband, Rachel Accurso spoke with two children being held at the Dilley Immigration Processing Center. She described the conversations as devastating.

“I don’t want to be here anymore,” he said. “Nothing is good here.”

Since early March, 9-year-old Deiver Henao Jimenez had been held with his parents at the Dilley Immigration Processing Center in South Texas, where children have complained of limited education, lights that never turn off and moldy food. Now he was on a video call with someone who said she wanted to help: Ms. Rachel.

Wearing her signature pink headband, the popular children’s entertainer leaned toward the screen, trying to comfort the boy.

“Oh, I’m so sorry,” she said in a warm, high-pitched voice familiar to millions of children and parents. “A lot of people want to try to help.”

Deiver told her he missed his friends and that the food at Dilley made his stomach hurt. But that wasn’t what worried him most. Before he was detained, he had won his school spelling bee and placed third at regionals, earning a spot at New Mexico’s state compeтιтion in May.

“I want to leave and go to the spelling bee,” he said.

Ms. Rachel tried to reᴀssure him.

“You have a real gift for spelling. You’re so smart.”

Then her smile faltered.

“It was unbelievably surreal to see this sweet little face and feel like I was on a call with somebody who’s in jail,” Ms. Rachel, whose real name is Rachel Accurso, told NBC News in an exclusive interview this week. “It broke me, and it was something I never thought I’d encounter in life.”

Like many Americans, Accurso said she first became aware of the family detention center in Dilley, Texas, in January, after federal immigration agents detained the father of 5-year-old Liam Conejo Ramos in Minneapolis and sent them both to the remote, prisonlike facility. A pH๏τograph of the child — wearing a blue bunny hat and a Spider-Man backpack — spread widely online, drawing national attention to the center and the treatment of families held there. They were eventually released but the family’s asylum claim was denied this week.

In the first year of its expanded immigration crackdown, the Trump administration placed more than 2,300 children into detention with their parents, with the overwhelming majority held at Dilley, according to figures provided by court-appointed monitors. Many have been held for several weeks or months.

During that time, Accurso — whose educational videos for babies and toddlers have made her one of the nation’s most recognizable kids’ entertainers — has become an increasingly prominent voice speaking out on behalf of vulnerable children. She has drawn attention to the plight of children in war-torn Gaza, Sudan and the Democratic Republic of Congo, raising hundreds of thousands of dollars and drawing backlash from critics who have accused her of picking sides in global conflicts.