TV Line confirmed the news, but so far there are no details about the storyline. Other than it features Superman, presumably. Maybe they’ve been on holiday together?
After being a regular character in season one, Cat has so far only appeared in the first two episodes of season two. You have to assume this will be a special guest appearance rather than a permanent return for the character. But we live in hope. Much like Flockhart does every time her hubby climbs into the cockpit of plane.