Grant Gustin is saying goodbye to "The Flash" after 9 years and is open to the idea of a "Glee" reboot.

Gustin played the villainous Sebastian Smythe on "Glee" from seasons 3-5.

Gustin had a great time on "Glee" and considers it one of the most fun experiences of his career.

Darren Criss, Chris Colfer and Naya Rivera were some of his co-stars on the show.

Gustin remembers Criss talking about the unpredictable nature of "Glee."

Gustin's memorable performances on "Glee" include "Live While We're Young," "Stand," "Glad You Came," and "Smooth Criminal."

Gustin considers himself a visitor on "Glee" and was honored to be a part of the show.

Gustin was overwhelmed by the talent on "Glee" and was nervous every hour he spent on the set.

Don't miss Grant Gustin's final act as The Flash on Wednesdays on The CW.