Stephen Amell will appear as Oliver Queen in the ninth episode of The Flash's final season.
The episode will be emotional and epic, featuring Amell and Grant Gustin saving the world together.
Amell's return is meant to create a full-circle moment for the show.
Other guest castings for the final season include Javicia Leslie and Nicole Maines.
The Flash's final season premieres on February 8th.
The showrunner said the episode is a thank you to the fans.
Amell recently said he would only return for a good storyline. He is now a star in the show Heels.
The episode will have thrills, chills, and tears.