Every "Pretty Little Liars" fan would like to know who 'A' really is. So, each of them hope that this upcoming Fan Appreciation Day on October 21, they can get a clear clue or answer to the identity of the most elusive character in the TV series.

ABC Family's teen mystery TV series will air "We Love You to Death" as part of its upcoming "13 Nights of Halloween", in which the cast will reveal their scariest experiences in the show. They will also answer their fans' "burning questions" posted on Twitter and Facebook with #PLLHalloween.

But it seems that some of the cast already know who 'A' is and they hinted they are now aware of who the mysterious character. In #PLL's latest teaser of "We Love You to Death", Troian Bellisario, who plays Spencer Hastings, said, "Yah, I know," when Shay Mitchell, known as Emily Fields TV series, read the question from a fan if the cast were told of who A is.

Meanwhile, Keegan Allen, portrays Toby Cavanaugh, tweeted, "Found out who THE -a is. Whoa. I'm... speechless. So I decided to tweet instead."

When a #PLL viewer asked Showrunner I. Marlene King via Twitter if it would take long before A is revealed, she replied, "closer than u think". Would this mean that the half of Season 5 is revelation time for the mysterious 'A' character?

After the special episode on October 21, "Pretty Little Liars" will be back for a Christmas episode "How the 'A' Stole Christmas" as part of ABC Family's 25 Days of Christmas. Perhaps, he or she would be the Grinch in the show.

Fans would think that if 'A' is finally revealed, then that could be the end of "Pretty Little Liars". However, we know that two more seasons are coming when ABC Family renewed the series prior to the Season 5 which secured Season 6 and 7 in mid-2015 and mid-2016, respectively.

If 'A' would be revealed, then most likely another mystery would be plotted to keep the show more interesting and most watched.