Oprah Winfrey is already talking about her 2-and-a-half hour "confession" interview with Lance Armstrong ... except she's not exactly revealing what he said to her. 

Oprah appeared on "CBS This Morning" to talk about the sit-down ... but nobody on the set -- including anchor Gayle King -- really pushed her about what Lance said.

Oprah DID say Lance confessed about using performance-enhancing drugs during his cycling career ... but added, "He did not come clean in the manner I expected."

But nobody followed up with questions about WHY Lance's answers were so unexpected.  READ MORE HERE!