New spoilers have been released for Pretty Little Liars season 4, including details on a new teacher and the relationship between Paige (Lindsay Shaw) and Emily (Shay Mitchell).

A new substitute teacher is coming to Rosewood High, according to a Tuesday report by E!Online. The teacher will be a "pretty" female in her 40s and will first appear in an episode called She's Come Undone. The report claims that the episode title may be referring to Aria (Lucy Hale).

In other Pretty Little Liars scoop, show writer Joseph Dougherty told Wetpaint in a recent interview that fans can expect more from the Paige-Emily relationship, which is often referred to as "Paily."

He revealed that episode 19, titled Shadow Play, would heavily feature Paige and Emily and please fans of the couple.

"I'm smiling now as you speak to me about it. There are some great Paily moments in there," Dougherty teased. "I think there are unexpected moments, and without digging too big a hole for myself, I think a lot of the Paily fans are going to be very satisfied by what we're doing."

The couple broke up in episode 9 of season 4 but they had gotten back together by the end of the summer finale. Dougherty's comments suggest that Paily will continue to function well as a couple.

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Dougherty discussed his pleasure in writing for Paily and how their success as a couple was a happy accident.

"The Paily thing has been very unexpected on all levels, but very satisfying," he explained. "Ever since I wrote the first kiss, it's always been exciting and unexpected between those two. And the actors are so exciting. It's such a pleasure to write those characters for them. When I want to feel self-important, I think it's important for that relationship to be in front of viewers to see what that's like."

The Halloween special of Pretty Little Liars airs Tuesday, Oct. 22 at 8 p.m. on ABC Family. Season 4 will go back to its regular schedule in January 2014.

Watch a promo for the episode here: