Stephen Colbert's real self was finally revealed (partially) on The Late Show with Stephen Colbert last night. The hopefully recurring bit "Who Am Me?" sets out to answer the question: "Is Stephen Colbert anything like his former persona on Comedy Central, 'Stephen Colbert'?" The answer is complicated. Stephen Colbert has been on TV for so long as someone else, some of his real self must have slipped out, and some of the persona must have influenced his real self. 

In order to find the truthiness of who he actually is, Stephen takes a personality test with a professional Myers-Briggs personality tester. The results are here:

Sources: The Late Show with Stephen Colbert