The leak led a special prosecutor's investigation of senior White House officials. In October of 2003, the Post said, Armitage admitted to senior State Department officials he had made the remark, which was based on a classified report he had read.
Novak's wrote his column after what he considered confirmation about Plame from senior presidential adviser Karl Rove.
The special prosecutor has never commented on Armitage's role and has not brought charges against him, the Post said.
The Post said Armitage did not return a phone call to his office but his former colleague said Armitage had described disclosing Plame's employment to Novak in an offhand manner. The report said Armitage did not know at the time Plame's identity was considered secret information.