english
1
general::
Phrase(s): That makes two of us. Inf. The same is true for me. • So you’re going to the football game? That makes two of us. • Bill: I just passed my biology test. Bob: That makes two of us!
McGrawhill's American Idioms And Phrasal Verbs
2
general::
I agree, me too, as in I'm sure it's going to rain.? That makes two of us. [First half of 1900s]
American Heritage Idioms