The I Kissed a Girl hitmaker was behind schedule on her way to meet Walters, and admits the broadcasting icon was less than impressed when she finally showed up.
Perry tells Billboard magazine, "When I got there, I apologised immediately, but then she said to me, 'You know, I've only ever waited for one other person this long, and you know who that person was? Judy Garland. You know how she turned out, right?'
"I was like, 'Oh, snap! Yes, b**ch!' I think it's the coolest thing that Barbara Walters shaded (trashed) me."
The singer now regrets agreeing to the sit-down talk as she was going through a difficult patch with her then-husband Russell Brand.
She adds, "I shouldn't have done the interview: I was playing Madison Square Garden (in New York City) that same night, and I knew that the end of my marriage was coming. I was just exhausted and stressed... (But) I just couldn't tell her as we were sitting down for a mega-interview, 'Hey, my marriage is falling apart. Give me a break.'"
Perry did not name the interview she sat for, but she appeared on Walters' Top 10 Most Fascinating People of 2011 - just weeks before Brand filed for divorce.