The actress played Jenna Sommers for the first two seasons of the drama on The CW before she was killed off.
Jenna will appear again through flashbacks in the episode airing May 10 in the US. The flashbacks focus on Elena's life before the beginning of the show, according to Zap2it.
The characters of Miranda and Grayson Gilbert - Elena's adoptive parents - have also been cast. Local Atlanta actors have signed up to briefly appear as them.
Since leaving The Vampire Diaries, Canning has featured in the Supernatural episode 'The Slice Girls' and guest-starred in Primeval: New World.
Vampire Diaries star Candice Accola, who plays Caroline, recently claimed that she cried reading the script for the third season finale.
> Read Digital Spy's recap of the episode 'Break On Through'
Watch a promo for the next episode 'The Murder of One' below: