Claim: Grant Gustin performed the role of Sebastian Smythe.

Thomas Grant Gustin -LRB- born January 14 , 1990 -RRB- is an American actor , singer , and dancer . He is known for his role as Barry Allen / the Flash -LRB- based on the DC Comics character of the same name -RRB- on the CW series The Flash and Arrow , both in the Arrowverse television franchise , and his role as Sebastian Smythe on the Fox series Glee .