(This post contains some spoilers for "Worlds Finest.")
Cat figured it out once already, and cited a number of observations from the first half of the season ("Hostile Takeover"). In particular, she knows Kara was able to overhear Dirk even though he wasn't in earshot, and there is no alternate explanation for that.
She knows James and Winn are Supergirl's sidekicks. She also knows James, Winn and Kara are good friends. Kara as sidekick is the glaring piece missing from this equation.
Cat knows Supergirl and the Flash worked together. Cat knew Barry was the Flash. She saw Barry hanging out with Kara, James and Winn, who all tried (and failed dismally) to explain who he was. At the end of the episode, Kara blatantly admitted that she, James and Winn had known Barry was the Flash, no doubt through their association with Supergirl.
She knows aliens and other superpowers exist, so even if she doesn't know exactly how Supergirl could have manufactured the illusion of Kara and Supergirl being in the same room, she must know that such illusions are possible.
We've seen throughout the series that she's very observant and very sharp, often waiting until the right moment to speak about something she's been observing for a while.
In "Worlds Finest", she said, "I still believe in Supergirl." Then she looked at Kara and said sharply, "And you should, too!" There seemed to be an enormous amount of subtext in that line. It seemed like the world's shortest and most timely pep talk, from someone who knew exactly what Supergirl needed to hear.
Out of all the people in the city, Kara was "randomly" or "mistakenly" kidnapped by Bizarro while on a date with Adam. What a coinkydink.
I'm sure there is more evidence I'm forgetting.
So, does Cat know Kara is Supergirl? Or have I just answered my own question?
Cat figured it out once already, and cited a number of observations from the first half of the season ("Hostile Takeover"). In particular, she knows Kara was able to overhear Dirk even though he wasn't in earshot, and there is no alternate explanation for that.
She knows James and Winn are Supergirl's sidekicks. She also knows James, Winn and Kara are good friends. Kara as sidekick is the glaring piece missing from this equation.
Cat knows Supergirl and the Flash worked together. Cat knew Barry was the Flash. She saw Barry hanging out with Kara, James and Winn, who all tried (and failed dismally) to explain who he was. At the end of the episode, Kara blatantly admitted that she, James and Winn had known Barry was the Flash, no doubt through their association with Supergirl.
She knows aliens and other superpowers exist, so even if she doesn't know exactly how Supergirl could have manufactured the illusion of Kara and Supergirl being in the same room, she must know that such illusions are possible.
We've seen throughout the series that she's very observant and very sharp, often waiting until the right moment to speak about something she's been observing for a while.
In "Worlds Finest", she said, "I still believe in Supergirl." Then she looked at Kara and said sharply, "And you should, too!" There seemed to be an enormous amount of subtext in that line. It seemed like the world's shortest and most timely pep talk, from someone who knew exactly what Supergirl needed to hear.
Out of all the people in the city, Kara was "randomly" or "mistakenly" kidnapped by Bizarro while on a date with Adam. What a coinkydink.
I'm sure there is more evidence I'm forgetting.
So, does Cat know Kara is Supergirl? Or have I just answered my own question?