one and the same

Determiner

idiomatic

(idiomatic) The same person or thing. Used to emphasize the identity or equivalence of two things.

Japanese Meaning

（慣用句）同一のもの、まさにそのままであること。つまり、二つの対象が全く同一であることを強調する表現。

Many fans were surprised to learn that the beloved author and the anonymous blogger were one and the same.

多くのファンは、人気作家と匿名のブロガーがまさに同一人物であると知って驚いた。

Sense（1）

(idiomatic) The same person or thing. Used to emphasize the identity or equivalence of two things.

It's almost as if there's one electron in two places at one and the same time.