the same one
Definitions
Identical to a previously mentioned or specified person or thing.
The exact individual or object already identified.
Examples
I bought a new shirt, but it turned out to be the same one my brother already owns.
If you are looking for the key to the front door, I think I have the same one in my pocket.
Synonyms
the identical one the very same that exact one the selfsame one the aforementioned one
Antonyms
a different one another one a distinct one the other one a separate one