‘Supergirl’ spoilers: New details on Grant Gustin appearance in ‘Worlds Finest’; plus, new poster!

Come March 28, “Supergirl” is bringing you an event that has been in some ways in demand from the moment it first premiered earlier this fall: A crossover event featuring The Flash. Grant Gustin is appearing in the episode entitled “Worlds Finest,” and CBS is clearly already having some fun marketing this story. The proof is in the poster above! It definitely feels like an old-school comic book, and putting Melissa Benoist and Grant Gustin on a racetrack was an inspired move for the sake of hyping this up even further.

The network also released today the first official details from the episode, which confirms that Silver Banshee and Livewire will be the two villains at the center of the story:

“Kara gains a new ally when the lightning-fast superhero The Flash (Grant Gustin) suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire, in exchange for her help in finding a way to return him home.”

As for how Livewire ends up escaping from the DEO, who currently has her captive, that is one of the mysteries going into the hour. Who knows? Maybe if things go well Barry can bring over Harrison Wells and Cisco next time to show them some of the skills they use for keeping criminals locked up at STAR Labs. (We’re kidding — sort of.)

We have no idea how any of this is going to play out, but at the same time, we don’t really care. we’re just excited to see this mash-up happen, and hopefully it’ll be the first of many that come over the next few years.

Interested in seeing some other news right now on “Supergirl”? Then be sure to head over to this link! Also, sign up over here now to get some further news on a flash via our official CarterMatt Newsletter. (Photo: CBS.)