The "Pretty Little Liars" book which was written by Sara Shepard has turned out to be one of the most popular television series. Apparently, the series continues to disclose certain secrets as every episode unfolds. Just recently, the series spilled a little secret on who are really the biggest bad.

Many were wondering about the real person behind A.D. Further, the series was also concerned on one of the show's characters Hanna Marin which was previously played by Ashley Benson. Right now, such role almost went to Sasha Pieterse or Ali DiLaurentis, Teen Vogue reported.

It can be recalled that "Pretty Little Liars" casts reunited over a live panel interview just recently. It was during that time when Pieterse revealed that she already had read the role of Hanna partially in a scene played together with Mona.

Further, it was also confirmed that Pieterse almost got the role when the PLL Twitter account tweeted about it the moment shortly after it had happened. Basically, it is no question for Pieterse to play any characters on the show.

On the other hand, there is a certain question that remained unanswered as to who is the biggest bad. The casts couldn't spill out yet about the real personality of AD. But Ashley Benson said that it was very shocking while Shay Mitchell said that the revelation is "amazing," Entertainment Online reported.

Executive producer Marlene King revealed that AD is a character that most of the fans already had seen before in the show. And basically, it is not going to be Alison's long lost third cousin as many would want to expect.

"Pretty Little Liars" recent update will give the audience a reminder that the crew and casts have almost completed the final season and is back for its final season by April 18 at 8 PM ET/PT.