Chyler Leigh as Alex, Melissa Benoist as Kara
Alex (Chyler Leigh) is about to come out to her mom Eliza (Helen Slater) when a breach suddenly pops up during their Thanksgiving meal. The CW

In a sneak peek of Season 2, episode 8 of “Supergirl,” Alex (Chyler Leigh) is about to come out to her mom Eliza (Helen Slater) during their Thanksgiving meal with Kara (Melissa Benoist), James (Mehcad Brooks), Winn (Jeremy Jordan) and Mon-El (Chris Wood) when her speech is interrupted by a breach that suddenly pops up right in front of them.

“Does that normally happen on Thanksgiving?” a confused Mon-El asks in the video.

“No,” replies Kara who instantly becomes so concerned with what they just saw.

This isn’t the first time Kara has seen a breach. In Season 1, episode 18, titled “Worlds Finest,” the Girl of Steel first saw a breach when she said goodbye to her Earth-1 friend Barry, aka The Flash (Grant Gustin), who suddenly found himself on her Earth while trying to increase his speed. Since Kara has already seen a breach before, she probably has a hunch that her speedster friend from another Earth is trying to pay her a visit.

As revealed in the synopsis for the episode, titled “Medusa,” Barry and his friend Cisco (Carlos Valdes) travel to Kara’s Earth to ask her join the battle against the Dominators who are about to invade the duo’s Earth.

“Arrow” and “Legends of Tomorrow” executive producer Marc Guggenheim said during a press Q&A last month that Earth-1 heroes will reach out to the Kryptonian soon after they find out that their home planet is about to be invaded by a group of aliens. “Once the heroes [in Earth-1] realize that they’re up against aliens, they decide that they need an alien on their side,” Guggenheim said (via Entertainment Weekly). “Fortunately, Barry knows a really nice one.”

“Last year, ‘Supergirl’ established that Flash was able to make his way to what I call Earth-CBS, and it stands to reason that, with the proper breach technology, the reverse can happen,” the exec producer added.”

“Medusa,” which starts the four-night crossover event between “Arrow,” “The Flash,” “Supergirl” and “Legends of Tomorrow,” airs on Monday, Nov. 28, at 8 p.m. EST on The CW.