Bosses at Washington, D.C. radio station Hot 99.5 have now released audio footage in which an emotional Gaga tells of her heartbreak on that tragic day, recalling how she ran away from her teachers at the Convent of the Sacred Heart to watch the second of the Twin Towers crumble.
The singer tells radio DJ Toby Knapp, "As a New Yorker, it's very intense. I've never really spoken about this before but I was in New York on September 11 and I watched the Towers fall with all my girlfriends from the roof of our school. The whole city was covered in ashes.
"There was a television playing (the news) and we were all crying (at school). I remember we broke into the playground on the roof and the teachers were all screaming at us to stay inside. But we couldn't even believe that it was real so we all broke in to the playground on the roof. I just remember we actually watched the second tower fall because in New York, you can see them from any roof, they were so big. We were all crying.
"I remember leaving the school, walking with my dad home. We saw all these really young guys from the (stock) market, from Wall Street, they were all covered in soot and all you could see was the water on their eyes from the tears. It was a really intense day... and I think for a lot of Americans it really was. You can see anyone's humanity in a moment like that."