Miss Martian and Supergirl are teaming up in season 2 of the The CW superheroine show. She'll be played by Sharon Leal.
With David Harewood shocking viewers in season 1 by revealing that his character was really Martian Manhunter and not Cyborg-Superman, fans have been anticipating the arrival of J'onn J'onzz's niece for quite a while. Although it's probably safe to say that no one expected M'gann M'orzz to show up THIS soon.
In addition, the Summer TCA panel for The CW also confirmed that Dolph Lundgren will appear on Arrow this season in flashbacks. If you recall, Oliver left Lian Yu at the end of season 4 to travel to Russia and free Taiana's people from captivity. It's assumed but unconfirmed at this stage that her people are being held by the Bratva (Russian mafia) and that this season's flashback will explain how Oliver got his tattoos and learned to speak Russian.
We don't know exactly who Lundgren will be playing but showrunners did say that he'll be a villain.
Arrow producers also reaffirmed that season 5 will be the last year of flashbacks on the show.
Sharon Leal will play Miss Martian.
It appears Stephen Amell is finding out the news about Dolph as the same time we are.