Pretty Little Liars
Pretty Little LiarsFacebook/Pretty Little Liars

"Pretty Little Liars" fans, who have read the book series, have for long been speculating Alison's twin to be the elusive A. But not only have PLL executives shot down the theory, they also said that Courtney will not be making an appearance on the television series.

Now, as season 5 inches towards its finale, PLL boss Marlene King decided to treat fans with a major bombshell, revealing that yet another twin theory could lead the way to unveiling A's identity.

"There is a reason why we keep dropping these not-so-subtle clues about the twins, so I would say wait for it," Marlene told ETOnline. "Wait for it. You're not going to see Courtney, but you may see double of someone."

All bets are on Mona, who is believed to be dead, having a twin, especially as Sasha Pieterse, who plays Alison, earlier said that if there was a twin in Rosewood, it's probably not for Alison.

Soon after King's major reveal, a number of fans have come with theories on how the rest of the season would play out. According to one Twitter user, whoever killed Mona took her body so she could return as Mona later on.

"I mean why would 'A' took Mona's body? well to come back later as Mona! while its not Mona it's her twin who is A. I mean, why else would they show us Mona's body ? it just makes the most sense," the tweet read.

Besides Mona, speculations are rife that the twin could be either Jason's or even Bethany's, but King revealed that no one has correctly guessed the motive behind A's attacks. "I will say yes, there has been more than one person who has identified 'A', but for all the wrong reasons," King explained.

If rumours doing the rounds are true, then the next episode will see the Alison being convicted of Mona's murder, and the Liars will also land behind bars for allegedly aiding the crime.

Tuesday's episode is titled "I'm a Good Girl, I Am" and based on the synopsis "Alison's trial is coming to a close, and the outcome looks even more bleak when the prosecution calls a surprise witness that not only paints Alison in a bad light but also the PLLs and Mike."

"Pretty Little Liars" airs Tuesdays at 8 p.m. on ABC Family.