Valerie Herrera, 17, in Chicago, was taking part in the pontiff's first-ever televised virtual audience with people in three American cities.
Francis spoke simultaneously with people in Los Angeles, McAllen in Texas, and at Cristo Rey Jesuit High School in Chicago's Pilsen neighbourhood.
"I would like to hear you singing. May I ask of you to sing a song for me? Be courageous," Pope Francis said.
"I was so nervous and we were talking and I started crying because of the nerves," said Valerie Herrera afterwards.
The virtual visits in Chicago and other parts of the U.S. was hosted by ABC News and took place ahead of the pope's historic trip to the country later this month, his first as pontiff.
Francis is due to address the United Nations General Assembly in New York and take part in a multi-religious service at the 9/11 Memorial and Museum at the World Trade Centre, as part of the six-day visit.
Pope Benedict was the last pontiff to visit the United States in 2008.
