Last week, CBS made the announcement that superhero fans had been waiting for, confirming thatThe FlashstarGrant Gustinwill appear in acrossoverepisode ofSupergirl. While no story details were given for this episode, it seems that production is already under way, withGrant Gustinsharing the first photos from the set, one of which features the actor alongsideSupergirlstarMelissa Benoist. Hopefully the actor will share even more images from the set as production continues on this episode.

TheSupergirlepisode will be broadcast Monday, March 28 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Ever sinceSupergirlwas picked up by CBS, fans had wondered if it was possible for this series to cross over withGreg BerlantiandAndrew Kreisberg’s showsArrowandThe Flashon The CW. While they do air on different networks, both CBS and Warner Bros. Entertainment actually own The CW, with the network’s name actually a combination of the first letters of its parent companies.

The crossover was teased even more during this week’s episode ofThe Flash, whenSupergirlwas spotted briefly asBarry Allenand his team travelled through the speed cannon. This seemingly confirms thatSupergirlis from another alternate universe, but we don’t know for sure quite yet. We’ll have to wait and see if Kara Zor-El makes any more surprise appearances inThe Flashas we get closer and closer to this episode.

If this episode is a success, then it could be possible forMelissa Benoistto cross over to Central City as well, or possibly evenArrow’sStar City. If these crossovers continue, it’s possible that otherSupergirlstars, such asMelissa Benoist,Mehcad Brooks,Chyler LeighandJeremy Jordan,David HarewoodandCalista Flockhartcould join Kara on a trip to Central City. There have been numerous crossovers betweenThe Flash,Arrowand the new seriesDC’s Legends of Tomorrow, but that’s to be expected since they’re all on the same network. This cross-network event could open up a whole new realm of crossover possibilities

While we wait for more details on this highly-anticipated episode, check outGrant Gustin’s photos from the set below. What do you think will happen when Barry meets Kara? Do you think we’ll get more clues to Kara’s “alternate universe” in upcoming episodes ofThe Flash? Chime in with your thoughts, and stay tuned for more updates.