The character of Jason DiLaurentis was recast and joined Pretty Little Liars as a recurring character in season 2 of the show.  But Alison's brother hasn't been seen since the August midseason finale (except for an appearance in the Halloween prequel episode).  When we last saw Jason, he showed up at the police station where the girls were being held after the cops found them with the murder weapon.

Spencer has been suspicious of Jason ever since he returned to Rosewood this season.  She's spotted some mysterious stuff in his house and for a while there it looked like he may have been stalking Aria.  While any potential relationship between Jason and Aria was put on hold, Spencer's suspicions were reignited when it looked like there was a connection between Jason and her father.  A lot of people (*spoilery speculation*) are speculating that Jason might turn out to be Spencer's brother, and it looks like the show might very well be heading in that direction.

While Jason has been absent since August, he's set to make a reappearance in the upcoming February 6 episode of Pretty Little Liars.  After someone framed Hanna for sending out a naked photo of her step-sister to her fellow students, Hanna and the other girls are forced to participate in Rosewood High's "Truth-Up Day", which is supposed to encourage children to share their feelings and confront one another about topics like bullying.  Aria is surprised when Jason walks in as a chaperone before the first session is about to begin.  When she explains to Caleb who Jason is, he suggests that him participating in "Truth-Up Day" might be a good idea, since it may force people to reveal some secrets (Jenna just happens to be in the audience as well).  Spencer is also forced to examine the possible connection between Jason and her father in the episode.

Watch a sneak peek below featuring Jason's return from the February 6 episode of Pretty Little Liars.  You can also watch two other sneak peeks for the episode here.