Why The Flash Cast Looks So Familiar

When Grant Gustin first appeared as Barry Allen in Season 2 of "Arrow," viewers were introduced to a clumsy crime scene investigator from Central City. As he went on to star in his own solo Arrowverse series, DC fans quickly grew accustomed to his portrayal of the Flash. Gustin is known for the emotional depth he brings to the hero, something executive producer Greg Berlanti saw during the audition process. "From the second Grant came in on his own, we kind of knew that he was Barry and not because he looked obviously like Barry from the comic book, 'cause he kinda didn't," Berlanti recalled in a featurette. "But [because] he had the heart you know, and Grant had the acting chops to carry this role."

Even though "The Flash" is the biggest role of his career to date, this wasn't actually the first show that put Gustin on everyone's radar. Before becoming the scarlet speedster, he first had his big break in 2011 when he was cast for a recurring part in the third season of Fox's popular musical dramedy "Glee." He portrayed Sebastian Smythe, the new captain of the Dalton Academy Warblers who was described as a "promiscuous and scheming male version of Naya Rivera's Santana," per TVLine. Even if he only appeared in a few episodes, his antagonistic portrayal of Sebastian was memorable due to the charm, wit, and confidence Gustin brought to the character.

His most notable musical performances from "Glee" were probably his covers of "I Want You Back" and "Smooth Criminal" with Rivera. The latter single even debuted at Number 10 on the Billboard Digital Songs chart. Despite switching his Warbler blazer out for a protective red suit, Gustin was still able to show off his musical prowess during a crossover episode in Season 3, when he and fellow "Glee" alum Melissa Benoist's Kara Danvers got stuck in a musical dream world.