'Ravenswood' casting: Merritt Patterson added as Tess

merritt-patterson-getty-ravenswood.jpgA heretofore unknown character has been added to the "Ravenswood" cast on ABC Family. Earlier this week, the "Pretty Little Liars" spin-off announced Brett Dier and Elizabeth Whitson have been cast as twins Abel and Olivia.

Now Merritt Patterson has been cast as Tess, ABC Family confirms to Zap2it (as first reported by THR). Tess is Olivia's former best friend -- who is not involved in the curse. "Ravenswood" focuses on five strangers who are connected by a mysterious and deadly curse.

Patterson tweets of her recent casting, "Thank you thank you thank you for all the love!! I feel it :) Sending it back to all of you xxo."

Dier, Whitson and Patterson join "PLL" regular Tyler Blackburn, who is leaving Rosewood for Ravenswood over the course of "PLL" Season 4 and the Halloween special airing in October.

"PLL" designer Fred Andrews also tweets the photo below, a tease for the spin-off captioned, "R is for ...."

Are you getting excited, "Ravenswood" fans?

r-is-for-ravenswood.jpg

Photo/Video credit: Twitter, Getty,