For Arrow fans who are already suffering from withdrawal symptoms as season 2 wrapped on Wednesday, the preview for the show's spin-off The Flash was revealed on May 15.

Olicity Moments In Finale Will 'Surprise,' 'Anger' Fans & Even Make Them 'Weep'?

In the preview clip, Oliver Queen (Stephen Amell) is seen giving advice to Barry Allen (Grant Gustin). Barry is the titular character of the show.

The Flash also stars Jesse L. Martin as Detective West, Rick Cosnett as Eddie Thawne (based on Professor Zoom), Danielle Panabaker as Caitlin Snow (based on Killer Frost), Candice Patton as Iris West, best friend of Barry, Carlos Valdes as Cisco Ramon (based on Vibe) and Tom Cavanagh as Harrison Wells, the creator of The Flash.

Slade's 'Specific Target' Will Comes As A 'Big Surprise To Everyone' In Finale?  

The Flash reportedly exists within the same universe as Arrow. Barry has appeared in Arrow on multiple occasions.

For fans who haven't watched the finale of Arrow's second season here's the official synopsis for Unthinkable:

Sara's Ex-Lover and League of Assassins Leader Nyssa al Ghul To Return in Finale?  

"Oliver must decide for once and for all if he is a killer or a hero - Slade (Manu Bennett) moves forward with his plan to kill one more person in Oliver's (Stephen Amell) life. While Oliver has fought all year to be more than the killer he once was, when Slade kidnaps someone close to Oliver's heart, Oliver is pushed to the edge and realizes sometimes it takes doing the unthinkable to stop the monster. Meanwhile, Diggle (David Ramsey) takes on Amanda Waller (guest star Cynthia Addai-Robinson) with a little help from some friends, and Thea (Willa Holland) turns to Roy (Colton Haynes) in her time of need. John Behring directed the episode with story by Greg Berlanti and teleplay by Marc Guggenheim & Andrew Kreisberg."

Unthinkable aired on May 14 on CW.

Watch the preview for The Flash: