The stakes are even higher for this year's "Arrow"/"Flash" crossover event, which will help launch The CW's next DC spinoff, "Legends of Tomorrow." The episode will unite new characters Hawkman and Hawkgirl with their fellow heroes to oppose Vandal Savage.

"The Flash" will kick off the crossover event on Tuesday, Dec. 1 on The CW followed by "Arrow" on Wednesday, Dec. 2. Executive producer Marc Guggenheim tweeted the first photo of Green Arrow (Stephen Amell), The Flash (Grant Gustin) and their team.

Unlike last year's crossover episodes, Green Arrow and The Flash will face a common villain, Vandal Savage (Casper Crump), the immortal caveman who will become the big baddie on "DC's Legends of Tomorrow," according to Comicbook.com.

"Most of the 'Flash' episode takes place in Star City, and most of the 'Arrow' episode takes place in Central City. We have a common villain, which was not the case last year, and just in general, we've done an excellent job of weaving not just two shows, but three shows together," Amell told Zap2It last month about the crossover.

In addition to Hawkman and Hawkgirl, the "Legends" team will include Firestorm - the duo Martin Stein (Victor Garber) and Jay Jackson (Franz Drameh), The Atom (Brandon Routh), White Canary (Caity Lotz), Heat Wave (Dominic Purcell), Captain Cold (Wentworth Miller) and the time-traveling Rip Hunter (Arthur Darvill).