Vampire Diaries co-creator Julie Plec recently revealed that she wanted Gillies to reprise his role as vampire Elijah on The Originals.
[Left: Daniel Gillies as Elijah, Right: Joseph Morgan as Klaus]
The show - which is yet to be officially picked up by the CW - would follow Elijah's brother Klaus (Joseph Morgan) as he returns to New Orleans to confront figures from his past.
Gillies has now signed up to appear alongside Morgan and Phoebe Tonkin, who plays werewolf Hayley, according to Deadline.
The Canadian star currently has a regular role opposite Smallville's Erica Durance on medical drama Saving Hope and is expected to shoot both shows simultaneously if The Originals receives a series order.
The April 25 episode of The Vampire Diaries - which will chart Klaus's New Orleans trip - will serve as a 'backdoor pilot' for the project. Julie Plec has scripted the special instalment and will also executive produce the potential series.
> CW boss on Vampire Diaries spinoff: 'Klaus is a great character'
Watch Daniel Gillies discuss his Vampire Diaries role below: