▁of ▁the ▁first ▁season , ▁" World s ▁Fin est ". ▁While ▁no ▁plot ▁details ▁on ▁the ▁episodes ▁were ▁released ▁at ▁the ▁time , ▁Ross ▁A . ▁Lincoln ▁of ▁Dead line ▁Hollywood ▁noted ▁that ▁" the ▁in - un iverse ▁reason " ▁for ▁the ▁c ros so ver ▁was ▁due ▁to ▁Barry ' s ▁ability ▁to ▁travel ▁to ▁various ▁dimensions , ▁thus ▁imp lying ▁that ▁Super g irl ▁exists ▁on ▁an ▁alternate ▁Earth ▁to ▁Ar row ▁and ▁The ▁Flash ▁in ▁a ▁mult iverse . ▁The ▁Flash ▁episode ▁" Wel come ▁to ▁Earth - 2 " ▁confirmed ▁this , ▁showing ▁an ▁image ▁of ▁Ben o ist ▁as ▁Super g irl ▁during ▁a ▁sequence ▁where ▁characters ▁travel ▁through ▁that ▁mult iverse . ▁The ▁earth ▁that ▁the ▁series ▁inhab its ▁is ▁Earth - 3 8 ▁in ▁the ▁Ar row verse ▁mult iverse , ▁and ▁has ▁been ▁inform ally ▁referred ▁to ▁as ▁" E arth - C BS " ▁by ▁Marc ▁G ug gen heim , ▁one ▁of ▁the ▁cre ators ▁of ▁Ar row . ▁ ▁During ▁the ▁second ▁season , ▁Super g irl ▁appears ▁in ▁" In vas ion ! ", ▁a ▁c ros so ver ▁episode ▁of ▁The ▁Flash , ▁Ar row ▁and ▁Leg ends ▁of ▁Tom orrow , ▁when ▁she ' s ▁rec ru ited ▁by ▁Barry ▁Allen ▁and ▁C is co ▁Ram on ▁at ▁the ▁end ▁of ▁" Med usa " ▁to ▁help ▁fight ▁off ▁an ▁invasion ▁by ▁the ▁Domin ators . ▁Super g irl ▁and ▁The ▁Flash ▁also ▁featured ▁in ▁a ▁musical