CHICAGO – Praise for a single mom seeking a better life for her child, strong words of support for US nuns, and encouragement for immigrants facing hardships in the United States.

Those are the topics students at Cristo Rey Jesuit High School said Pope Francis touched on during a “virtual audience” with them Monday.

The school was selected by the Vatican last spring to join two other groups — homeless people in Los Angeles as well as immigrants at a Catholic parish near the US-Mexico border — for an hour-long conversation with a “world leader.” Administrators didn’t find out until late last week that it was Francis who would be addressing about 145 students and 25 faculty gathered in the school’s chapel.

Though Francis spoke some English, the event was conducted primarily in Spanish, students said, with the pope’s remarks translated into English.

Excerpts aired on ABC News Monday evening, with an hour-long special scheduled for Friday, according to a press release from the network. The event was moderated by ABC World News Tonight anchor David Muir and featured gatherings in three cities the pope won’t get to see during his US visit.

Rafael Diaz, a sophomore at the high school, said Francis addressed family issues, praising a single mother who emigrated with her daughter to the United States in search of a better life for her child.

“He said to always fight,” Diaz said. He said the bulk of the pope’s message was reminding participants that God is always near, even in the most desperate of situations.

During the event, Francis asked a teenage girl to sing for him as he sought prayers for his upcoming trip to the United States.

The 17-year-old girl in Chicago, Valerie Herrera, a high school senior, wept as she told Francis she’d been bullied because of a rare skin condition and had turned to music for comfort. He said in English he would like to hear her sing. When she hesitated, he told her to “be courageous.”

“I was so nervous, and we were talking and I started crying because of the nerves,” Herrera told WLS-TV in Chicago.

She said she learned the song, “By You, Mary,” years ago in choir and it’s the first one that came to mind. She sang in Spanish, and he smiled and thanked her.

Pope Francis will address the World Meeting of Families in Philadelphia as part of his US visit, and his comments praising the single mom come in the midst of a heated Church debate about family life that will continue in October at the Synod on the Family in Rome.

Almost all of the audience had no idea it was Pope Francis until his image was beamed onto special screens set up for the conversation.

Michael Frutos, a senior at Cristo Rey, said he didn’t believe what he was seeing.

“I thought it was a joke, that they were pranking us,” he said.

Two people from each location addressed the pope, telling their personal stories and receiving feedback from the pope.

Cristo Rey Jesuit High School was founded in 1996 and has about 565 students. Located in Chicago’s Pilsen neighborhood, it’s part of the Cristo Rey Network of schools, in which students work five days each month in order to pay their tuition and earn work experience at local businesses.

Material from the Associated Press was used in this report.