Superman's Girl Friend Lois Lane #94 (1969)

The Lois Lane in the Mystic Mirror / Superman's Flight from Lois Lane
Lois Lane accepts an invitation from the Lois Lane of Terra, the Earth of another universe, to take her place as the wife of her world's Superman and the mother of their child. She enters through a magic mirror she was given by Cagliostro II, a stage magician, but is warned that she can never return to Earth again. A mishap in the other world causes Lois and Jor-El II, the other Lois's son, to become invisible, blocking them from the other Superman's sight, and Cagliostro II, ruing the trouble his magic mirror has caused, breaks it, stranding the two Loises in the universes they currently occupy.
Release Date: 1969