Sebastian/Thomas will serve as Lizzie Saltzman's new love-interest, joining the Salvatore School for the Young and Gifted.
Seventeen.com got to chat to Thomas about his new role, where he dished on being compared to Damon.
"I think we definitely share that same energy. We have a very similar energy and expressions where we also have this charming, brooding quality to them. You'll just have to wait and see if they're similar and make your own mind up."
While Thomas won't actually be playing Damon, he understands he has some big shoes to fill being compared to the hunky Vampire.
"It's always flattering to be compared to someone everyone loved in the series and who is a very successful and incredible actor. I think when I was working for Disney, I kept getting compared to Zac Efron and Troy Bolton and stuff, so that was natural to that.
"I mean, I try to not let that affect what you're trying to do for your character. They are completely different characters and he's also done his fantastically well and you don't just want to copy that.
"You want to give the audience something different. Something else that they can either relate to or not relate to. Enjoy or not enjoy. That's the whole essence of what we do."