EXCLUSIVE: 'Pretty Little Liars' Boss Spills on 'A's Heartfelt Reveal: 'It Had to Be This Person'

To help get you prepared for tonight's mind-blowing finale, ETonline is bringing not one, but TWO spoiler-packed interviews!

It's here -- it's finally here!

After five and a half seasons of text message torments, nightmare-inducing presents, and multiple near-death experiences, it's time to come face-to-face with 'A' in tonight's Pretty Little Liars summer finale.

To help get you prepared for tonight's sure-to-be mind-blowing finale, ETonline is bringing you not one, but two spoiler-packed interviews!

Press play on our video above to watch PLL star Shay Mitchell and executive producer Marlene King reveal which of the series biggest questions will be answered.

Then, scroll down and read our in-depth interview with King to find out how long fans will have to wait before their answered are revealed, the lengths they've gone to keep the identity of 'A' a secret, and why this finale is the most "heartfelt" episode we've ever seen.

WATCH: 'PLL' Boss Talks Time-Jump Weddings & Revealing 'A'

How would you describe Tuesday's face-to-face finale with 'A'?
Marlene King:
It's very heartfelt. There are certain scenes where you see 'A' as a young child several times in the finale, and it's just like, 'Oh my God!' It's just such a great story, I'm really proud of it.

How long will fans have to wait before we come face to face with 'A' in the finale?
Originally I wanted to show 'A's identity in the teaser, in the very first scene, and have the rest of the first episode be the how, and then why -- but the network asked me to push it. At least to the end of the first act, so that people who are late to the party won't miss it. It's designed that way for a reason because everyone has their own favorites of who they want to be 'A' and no matter who it is, there will be certain group of people upon that initial face who will say, 'Oh I didn’t want it to be that person!' But I think the story is so compelling that for the rest of the episode getting to hear the story, and see the story play out of how 'A' became 'A', you realize that there could be no other 'A'. It had to be this person.

So they only have to wait about 15 minutes or so?
Maybe 20, I don’t remember how long it is.

NEWS: 'PLL' Stars React to 'A's Identity: 'I Was Shocked!'

What precautions have you been taking to ensure that 'A's identity has not been leaked or spoiled before the finale?
Oh my gosh, so much! It's like we had somebody from the CIA in here outfitting our computers and installing this software so that people cannot hack us, because we have been hacked in the past. People are constantly trying to hack us. We started delivering scripts the old fashioned way so everything was watermarked. Even when [the episodes] are outsourced to the people who do the subtitles and stuff like that, everybody has to sign non-disclosure agreements. Knock on wood we have been able to keep the secret.

You've promised that we will find out the identity of 'A', Red Coat and Black Widow -- So should we be expecting to see three different faces in the finale?
It's more than one person -- that we know because we saw them sitting together a couple of episodes ago. That was crazy! Most people thought that Red Coat was Black Hoodie or Alison. Aria even says that in the finale, she says, "Wait there's another one? There's two of them?!"

ABC Family

In these last few episodes, it almost seems like Ali has started to empathize with 'A'…
Well, 'A' is her brother.

But does that mean that fans should forget that 'A' has spent the last five seasons tormenting the Liars with all of these horrible things?
No, and that’s very much a part of the dynamic of the finale. As we hear the story of 'A' and understand some of the motivations. Like you cannot just forget what happened and that's really what is a big part of the emotional journey that all of the characters go on during the finale.

WATCH: Discover All the Secrets of the PLL Wardrobe Trailer!

When you finally got to tell the cast as a whole, what was their reaction to 'A'?
Everybody loves hearing the story. Even when I started pitching it years before the cast even knew. We didn’t tell the network until last year who it was. People's mouths just dropped because it all clicked, and it was so layered, and it just made so much sense, and you just know it's good.

What is the one thing you want fans to know before tuning in to the finale?
Just to know that it's no lie. I know that other finales have been promoted in ways that make you think you're going to get all the answers, but this really is the one. There's no denying it, there's no lie, it is the absolute end to the story of this 'A', and the Pretty Little Liars in high school, and the story that we really started to tell in the pilot. It's really ending and there's a very complete end to this circle.

Pretty Little Liars
' summer finale airs tonight at 8 p.m. ET/PT on ABC Family.

What do you think 'A' is? Share your thoughts with @LeanneAguilera and live-tweet with @ETnow during tonight's east coast airing of the episode! And make sure to check back to ETonline immediately after the hour for even more explanations from Marlene King!