This time, Andrew Kreisberg told us and a group of other reporters at a recent set visit that he's not even sure if such a crossover is a legal possibility.
"There's always those late nights, delirious, semi-high on pizza where you're like, 'You know what would be really cool? If …,' "Kreisberg said. "But right now there is no legitimate actual plan to bring [The Flash's] Cisco [Carlos Valdes] onto Supergirl or to bring [Supergirl's] Winn [Jeremy Jordan] onto Legends [of Tomorrow]. First of all, we don't even know if we could, legally. And quite frankly, just making the Arrow-verse, which is what we call Legends, Flash and Arrow work and then making Supergirl work, it's enough of a challenge without having to add a fourth player."
Fans will just have to enjoy their superhero chocolate and peanut butter separately for the time being.
Supergirl airs Mondays at 8 p.m. ET on CBS.
The Flash airs Tuesdays at 8 p.m. ET on the CW.