While we continue our push to cast Phoebe Tonkin on The Vampire Diaries, we have exciting news one of that actress' former co-stars.

Jessica Parker Kennedy - best known for portraying Melissa on The Secret Circle - will guest stars on Season 5 of 90210.

According to Deadline, the actress will appear on multiple episodes as "a girl next door who tells her story in group therapy." To whom? Which main character will be involved in her storyline? Take your best guess now!

Elsewhere, General Hospital veteran Jason Thompson has also been added to the cast... as a detective! On a major investigation! Again, let those theories fly! He'll debut on Episode 3.

90210 returns on October 8.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.