We finally have some dates to put on our calendars for The CW's annual Arrowverse crossover event!

This year, Arrow, Supergirl and The Flash will take part in the crossover episodes (DC's Legends of Tomorrow will not), which are slated to air this December. Happily holidays to us! The Flash will kick off the three-part crossover on Sunday Dec. 9, with Arrow following on Monday, Dec. 10 and Supergirl finishing things off on Tuesday, Dec. 11. Note that Supergirl and The Flash will trade time slots for this one week only!

Plot details about the crossover episodes are being kept under lock and key for now, but we do know that this event will mark the first appearance of Batwoman (Ruby Rose) in the Arrowverse. Considering the first appearance of Barry Allen (Grant Gustin) on Arrow is what eventually launched The Flash as the Arrowverse's first spin-off series, we wouldn't be surprised if a successful launch of Rose's character, Kate Kane, in this crossover leads to green light for the Batwoman series currently in development at The CW.

The Flash premieres Tuesday, Oct. 9 at 8/7c, Supergirl premieres Sunday, Oct. 14 at 8/7c, and Arrow premieres Monday, Oct. 15 at 8/7c on The CW.

(Full disclosure: TV Guide is owned by CBS, one of The CW's parent companies.)

Melissa Benoist, Stephen Amell and Grant Gustin, <em>Legends of Tomorrow</em>Melissa Benoist, Stephen Amell and Grant Gustin, Legends of Tomorrow