Grant Gustin, star of The CW’s hit superhero series “The Flash,” will visit CBS’ “Supergirl” for a crossover episode set to air Monday, March 28 at 8 p.m. on CBS, it was announced Wednesday.

Plot details for the episode, titled “Worlds Finest” — including what will bring Barry Allen (Gustin) to National City to meet titular heroine Kara Danvers (Melissa Benoist) — are set to be announced at a later date.

“We are so incredibly excited to announce something that we have dreamed of happening since we started making ‘Supergirl’ – The Flash and Supergirl are teaming up!” said “Flash” and “Supergirl” executive producers Greg Berlanti and Andrew Kreisberg. “We want to thank Grant Gustin for making the time to come visit (on top of his already immense workload) and all of the folks at CBS, The CW, Warner Bros. and DC for working this out. And finally thanks to the fans and journalists who have kept asking for this to happen. It is our pleasure and hope to create an episode worthy of everyone’s enthusiasm and support.”

The episode, which will be the 18th installment of “Supergirl’s” freshman season, was penned by Kreisberg and Michael Grassi, from a story by Berlanti. Gustin shared the cover page from the script via Instagram after the news was announced.

This won’t be the first time that Gustin and Benoist have united — the pair took part in a cover shoot for Variety to celebrate Berlanti’s superhero success last year.

Berlanti approached a potential “Supergirl” crossover in cautious terms at the time, telling Variety, “[CBS] has said publicly at this point they’re going to keep her to themselves. I always approach the shows as a fan first, so I would love to see [a crossover]. I think in success, all things are possible. But there’s a lot that would have to happen before everybody might say yes to that.”

The CW’s boss, Mark Pedowitz, has always been open to the idea of cross-pollination between the network’s superhero properties and CBS’, telling reporters at the network’s Television Critics Assn. panel, “I leave that to Greg Berlanti and his team. If they can make it work, that’s great. If they cannot, that’s fine. We are open to crossovers … That’s Greg’s call because he understands his shows better than I do because he’s there.”

Gustin is no stranger to crossovers — “The Flash” is a spinoff from Berlanti and Kreisberg’s first CW superhero show, “Arrow,” and the two series have mounted multiple crossover events over the past two seasons. The two shows also spawned The CW’s midseason hit “DC’s Legends of Tomorrow,” which centers around supporting characters introduced on “Arrow” and “Flash.”

“The Flash” currently stands as The CW’s highest rated show. “Supergirl” is CBS’ top new of the 2015-16 season and ranks sixth on the network in the 18-49 demo.

“Flash” is averaging a 2.3 in 18-49 and 5.7 million viewers overall in its second season, while “Supergirl” is averaging a 2.8 and 11.2 million viewers overall.

“Supergirl,” which airs Mondays on CBS, stars Melissa Benoist as the titular heroine, alongside Mehcad Brooks, Chyler Leigh and Jeremy Jordan, with David Harewood and Calista Flockhart. The series is produced by Berlanti Productions in association with Warner Bros. Television. Berlanti, Kreisberg, Ali Adler and Sarah Schechter are executive producers of “Supergirl,” which is based on the characters appearing in DC Comics, and created by Jerry Siegel and Joe Shuster, by special arrangement with the Jerry Siegel Family.

“The Flash” airs Tuesdays at 8 p.m. on The CW, and is produced by Bonanza Productions Inc. in association with Berlanti Productions and Warner Bros. Television. Gustin stars, with Candice Patton, Danielle Panabaker, Carlos Valdes, Tom Cavanagh and Jesse L. Martin. Berlanti, Kreisberg, Schechter, Todd Helbing and Aaron Helbing are the executive producers.