AceShowbiz -

As "Pretty Little Liars" is believed to be coming to its end with its currently airing seventh season, the big bad is expected to be revealed this season. Recently, fans have been speculating about who A.D. a.k.a. Uber A is and one particular theory is so shocking that we wish it's not right.

The theory that has been floating suggests that A.D. could stand for Aria Drake, meaning Lucy Hale's character who has been one of the show's heroines is apparently the culprit they have been looking for. This is affirmed by recent revelations that Mary Drake gave birth to another child after Charlotte and that child in question would now be the Liars' age.

Moreover, A.D. stole Aria and Noel's files from Jessica's cellar. While A.D. burnt Noel's file, Aria's was kept. Fans may also remember that Byron's brother Scott (Aria's uncle) also suffered from mental illness. It's suggested that Scott could have impregnated Mary when they were treated at Radley.

Of course, there are other speculations pointing at different characters as Uber A. And while the show is not giving away the answer yet, fans are free to guess who the big bad is.

In other news, EW reports that Chloe Bridges will reprise her role as Sydney Driscoll on the show. Chloe was part of Mona's army in season 5. When Mona was believed to be murdered, Sydney and Jenna thought Ali was behind it.

"Pretty Little Liars" airs Tuesdays at 8/7c on Freeform.