For a long time, I had only known the phrase "matter of fact" to be used in "as a matter of fact..." However, for quite a few days, I have also been hearing, "the fact of the matter is..." in news debates.
Are these one and the same? If not, how and where they can be used?
Assuming that you meant "matter of fact" (as opposed to "matter of the fact"), there is a difference between the two idioms.
"Matter of fact" (often used in a sentence as 'as a matter of fact, ...") is described by Mirriam-Webster as:
adhering to the unembellished facts; also : being plain, straightforward, or unemotional
Often the phrase is used to explain that a previously stated 'fact' or detail which was thought to be unlikely actually is in fact true or alternatively to counter a previous statement. Examples (from The Free Dictionary:
"As a matter of fact, John came into the room while you were talking about him."
"I'm not a poor worker. As a matter of fact, I'm very efficient."
"Fact of the matter" means simply "the truth". It's typically used to emphasize a fact (perhaps one that has been debated) but which isn't really a valid thing to debate about.
"The fact of the matter is that unless we drive faster, we wont arrive on time."
