'The Perfectionists' news: 'Pretty Little Liars' spinoff adds 'Descendants' alum Sofia Carson

Sofia Carson in "Descendants 2."Disney

"The Perfectionists" is finally starting to take shape. Not long after it has been confirmed that the script is already being written, the "Pretty Little Liars" spinoff has added Disney star Sofia Carson to its cast.

The official Twitter page of "Pretty Little Liars" announced the news on Monday. Carson herself celebrated her casting with a tweet of her own, saying: "Secrets out. I'm a PRETTY. LITTLE. LIAR."

Best known as Evie in Mouse House's "Descendants," the 24-year-old actress will play the role of Ava Jajali who is described as "a stylish trendsetter with a big personality" and "hopes to have her own clothing line someday. But she has an edge over her fellow fashionistas: a brilliant technological mind, which she uses to blog and code."

She will be joining Janel Parrish and Sasha Pieterse, who are reprising their original "Pretty Little Liars" roles, Mona and Alison, respectively. Both have since welcomed her to the Liars family alongside author Sarah Shepard and "Pretty Little Liars" alumn Lucy Hale, a.k.a. Aria in the parent show, who congratulated her for her new gig.

Based on Shepard's novel series of the same name, "The Perfectionists" takes place two years after the "Pretty Little Liars" finale. As reported previously, it follows five high school students — Ava, Caitlin, Mackenzie, Julie, and Parker — who are bonded together by their mutual hatred of a bully named Nolan Hotchkiss. In the books, the group jokingly comes up with a plan to murder the boy, who later ends up dead the way they planned. The problem, however, is that they were not the ones who did it.

As it is a spinoff of "Pretty Little Liars," "The Perfectionists" will be tonally similar to the original show. As King explained to TV Line, "There is a big mystery, and there is a murder, and there are some characters who are a fractured group at the beginning of our story, and through a murder they become friends. So it's similar in that regard, but it's a whole new mystery, a whole new murder."

"The Perfectionists" has no premiere date yet.