"Arrow" fans can look forward to an exciting new episode next week that will feature a dynamic crossover with "The Flash" and introduce the upcoming spin-off series "Legends of Tomorrow."

The two-part crossover episode will air Part 1 on "The Flash" on Dec. 1, while the second part will air on Dec. 2 on "Arrow." A synopsis for the upcoming installment reveals that Team Arrow will join forces with Barry and his squad to take down an immortal villain named Vandal Savage.

"Oliver (Stephen Amell) and Barry Allen (guest star Grant Gustin) take Kendra Saunders (guest star Ciara Renée) and Carter Hall (guest star Falk Henstchel) to a remote location to keep them hidden from Vandal Savage (guest star Casper Crump) while they figure out how to defeat him. Malcolm (John Barrowman) arranges a meeting between Vandal, Green Arrow and The Flash that doesn't go as planned. Meanwhile, Felicity (Emily Bett Rickards), Thea (Willa Holland), Diggle (David Ramsey) and Laurel (Katie Cassidy) work with Team Flash to come up with a weapon powerful enough to destroy Vandal Savage," states the synopsis, according to CarterMatt.

"Arrow" executive producer Marc Guggenheim also teased that fans can expect to see Colton Haynes reprise his role as Roy Harper in early 2016.

"We are beyond thrilled that Colton will be returning to Arrow this season ... It was always our intention to have him return following his departure last season, but it was a matter of finding the right storyline to pull it off. That opportunity presented itself in Episode 412, and we can't wait for the fans to see this reunion," he said, reports CarterMatt.

However, Roy's return may cause some drama since his ex-girlfriend, Thea Queen, now has found a new love interest in Oliver's campaign manager, Alex (Parker Young).

It has also been revealed that Roy will return to Star City after he is blackmailed by a new character named Noah Kutter aka The Calculator. According to TVLine, actor Tom Amandes has been cast to play Kutter, who is described as a brilliant computer tech who excells at manipulating others in order to fulfill his personal agenda. In addition to blackmailing Roy, he will try to get him to face off against Team Arrow in an epic showdown in Star City.

Meanwhile, executive producer Wendy Mericle also dropped spoilers, revealing that viewers will finally learn more about Felicity's father, who she confirmed is not Damien Darhk.

"We are actually figuring out Felicity's father as we speak," she told Entertainment Weekly. "It's not going to be tied to H.I.V.E. It's going to be something that is more personal, emotional, speaks directly to her story, and a big bombshell that's going to be coming out - a big reveal between her and Oliver later in the story - and the story is going to really speak to that."

"Arrow" Season 4, Episode 8 will air on Wednesday, Dec. 2 at 8 p.m. ET.

Watch a preview video below.