Come To Mention It Meaning

(idiomatic) What you just said reminds me of something; Used to justify a change of subject or a kind of statement that needs some kind of license.

Example:   "What do you think of the banking reforms?" / "Come to mention it, I've got to get to the bank before it closes today.
  "Did you see that hat he was wearing?" / "Come to mention it, he always wears funny clothes."