The story came up Monday at a Tribeca Film Festival press conference where a journalist asked Spacey if he ever used his famous name to get something he wanted.
"I used to walk up to Broadway theaters when I was starting out and broke and wanted to go see a play and because I had been doing standup comedy and I did a Johnny Carson impression, I would pretend at the box office to be Kevin Carson," Spacey recalled.
"The most surprising thing is I usually got in," the double Oscar-winner said, adding he would use a Johnny Carson-like voice and tell the ticket clerks someone from The Tonight Show had secured entrance for him.
"It was always early previews and they wanted the house to be filled, so they'd give me tickets... So, in a sense, I used Johnny Carson's celebrity to get into theaters."
The question then went to Spacey's co-star Michael Shannon, who was sitting beside him on the panel.
"Speaking of late-night, talk-show hosts, I'm just glad that I got on Letterman before he retired. That's about it," said Shannon, whose other film credits include 99 Homes, The Iceman, Take Shelter, Man of Steel and Midnight Special.