This December, The CW is airing a legen--wait for it--dary four-night, four-way crossover event with "Arrow," "The Flash," "Supergirl," and "DC's Legends of Tomorrow."

Stephen Amell (Oliver Queen/Green Arrow) teased a casual gathering of superheroes in a photo with Grant Gustin's Barry Allen/The Flash, Melissa Benoist's Kara Danvers/Supergirl, Caity Lotz's Sara Lance/White Canary, and Brandon Routh's Ray Palmer/The Atom.

Here it is:

It's a bird, it's a plane ... it's super-feet!

Amell didn't add any details, and TVLine noted that it's a bit early for them to actually be filming the December episodes, so they were probably gathering for a fall promotional shoot.

Back in May, CW chief Mark Pedowitz announced this latest event: "Next season, Arrow, The Flash, Legends of Tomorrow, and now Supergirl will join forces in our annual crossover event, our biggest ever."

Biggest ever! "The Flash" Season 3 premieres October 4. "Arrow" Season 5 premieres October 5. "Legends of Tomorrow" Season 2 premieres October 13. And "Supergirl" makes its move from CBS to The CW in Season 2, which premieres October 10.

You know who'll also be on "Supergirl" early in Season 2? He showed up in another Stephen Amell tease:

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