Come to think of it is said when a new thought strikes you mid-sentence. Come to think of it, he was there too.
It marks a genuine change of mind out loud, which is why it makes a speaker sound honest. It goes at the front of the sentence it introduces.
1phrasecome to think of itSaid when a new thought strikes you mid-sentence.
“Come to think of it, the car was already gone by then.”
come to think of it is a phrase.
Practised in Small Talk & Everyday Phrases