He assumed a new identity.

He looks like a completely different person to what he was before.

He is a different person from the one we are looking for.

He has become another man since getting married.

The man who I thought was his father proved to be a perfect stranger.

I feel like another person.

Discipline transformed the child.

The girl who I thought was a singer proved to be a different person.

I look very different.

I feel like another person.

I feel like a brand new person.