Video: Supergirl, The Flash Stars Talk Crossover Chemistry, James' Jealousy

No wonder James Olsen is feeling a little green with jealousy.

The friendly rapport between Melissa Benoist and Grant Gustin‘s superheroes — and the actors themselves — is on full display in this behind-the-scenes video for Supergirl‘s crossover with The Flash (airing Monday at 8/7c, on CBS).

“They have such good chemistry because there’s this joy about them and humor and lightheartedness,” Benoist says in the featurette. (Try to resist her excited laugh about the crossover. We dare you!)

Barry Allen’s improbable arrival yields different responses from Kara’s friends. In a glimpse at some new footage, Winn (played by Jeremy Jordan) is beyond excited to learn their new pal comes from another universe, while James (Mehcad Brooks) wonders, “How could you travel that fast?” Cue Barry giving him and Kara a demonstration of his abilities — and ice cream cones, to boot!

Also glimpsed in the preview: a Three Musketeers reference from the Scarlet Speedster, a scary turn from Siobhan’s Silver Banshee and that much-hyped race to see who’s faster.

Press PLAY above to watch, then hit the comments with your hopes for the special crossover event.