New York (CNN) Lady Gaga made a powerful announcement to a group of young LGBT people in New York -- she suffers from post traumatic stress disorder.

Gaga revealed that she suffers from the debilitating mental illness at Harlem's Ali Forney Center for homeless LGBT youth on November 25. The taped segment aired on NBC's "Today" show Friday.

She visited the center as part of a collaboration between her foundation, Born This Way, and the NBC morning show. She brought along clothing, gifts and donuts.

Today I shared one my deepest secrets w/ the world. Secrets keep you sick w/ shame ❤️Watch this video #ShareKindness https://t.co/Rynfxekz3Z

She also spent a few hours sharing her own struggles and experiences, including her battle with mental illness.

Gaga revealed rape in 2014

In 2014, Gaga publicly revealed that she had been raped when she was 19. Her Oscar-nominated song, "Til It Happens To You," focuses on the experience of being sexually assaulted. The song was featured in the documentary, "The Hunting Ground," about sexual assault on campus.

"My own trauma in my life has helped me to understand the trauma of others," Gaga said in an interview with the "Today" show. "I told the kids today that I suffer from a mental illness. I suffer from PTSD. I've never told that to anyone before, so here we are."

JUST WATCHED The mental cost of trauma Replay More Videos ... MUST WATCH The mental cost of trauma 01:19

Gaga did a meditation exercise with the young people to show them how she deals with stress.

"Meditation helps me to calm down," she told the group during her visit. "I don't have the same kinds of issues that you have, but I have a mental illness and I struggle with that mental illness every day so I need my mantra to help keep me relaxed."

Visit a surprise to most at center

Gaga performed "Million Reasons," one of the songs from her latest album, "Joanne," for the group. She also let every staff member and teen take a selfie with her individually, the center's founder and Executive Director, Carl Siciliano, told CNN.

"Lady Gaga has always been extraordinarily supportive of the LGBT community," Siciliano said. "She was remarkably unguarded, open and available to each individual young person."

The visit was a surprise to most of the staff and the 60 to 70 teens at the center. As soon as they saw her come in, the group just started screaming, Siciliano said.

To the LGBTQ's @AliForneyCenter thank you for sharing your stories, trauma & pain with me & the world today. Your kindness is contagious. ❤️ — xoxo, Joanne (@ladygaga) December 5, 2016

He said 75% of young people that come to the center say they were subjected to either physical or sexual abuse in their homes because their parents couldn't accept them being LGBT.

Center named for murder victim

"To have somebody so famous, celebrated and valued in our society kind of showed them that they are worth being cared about and worth being loved when they often feel so dramatically invalidated," Siciliano said. "It was very moving and meaningful to them."

Siciliano founded the Ali Forney Center in 2002. He named it after a homeless gender nonconforming person who he worked with at a different homeless drop-in center, Ali Forney. Forney was murdered on the streets of Harlem in 1997.

His murder is still unsolved. At that time, there were no homeless shelters for LGBT people only. The day the Lady Gaga segment aired on the "Today" show was the 19th anniversary of his death.