According to some recent reports, Cooper had expressed interest in starring in the project, which will be produced by filmmaker JJ Abrams.
But the 38-year-old actor said he had never shown any interest in the movie, reported Aceshowbiz.
"No. Oh my God, that's so nuts!," Cooper said.
Explaining what really happened during the interview, Cooper said, "I was in Manchester, doing the BBC morning show... I had no idea what the interviewer was talking about. I didn't even know that JJ has the rights, I had no idea. I don't know anything about it."
Asked about the idea of starring as Armstrong in a movie, he said, "I would be interested in that. I think he's fascinating. What a fascinating character."
Paramount Pictures is currently developing a film about the athlete which will be based on a proposal book called "Cycles of Lies: The Fall of Lance Armstrong".