I saw, but did not know him [Imam Mahdī (mgehr)]….
Sometimes [they] ask if it is possible, that Imam Mahdī (mgehr) knows them but they do not know him?
The answer is yes
[As] It is stated in the Holy Qur`an, Prophet Joseph(pbuh) knew his brothers after about forty years of being thrown down to the well [by his brothers] till being given power[by the king of Egypt].
But they did not know him.