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Tonight's episode of Pretty Little Liars is the one we've all been waiting for: the "Big 'A' Reveal." ABC Family's mystery series has faked us out when it comes to the identity of its most elusive character before, but tonight's season five finale promises to spill some serious deets. And in true PLL fashion, you never know what to expect. The show's star Ian Harding stopped by InStyle’s offices last week, and we tried to get the man behind English-teacher-turned-coffee-shop-owner Ezra Fitz to fill us in about the series' biggest mystery: 'A.' Unfortunately, we discovered that even Harding is still in the dark on that one. "I really don't know who 'A' is," he said.

Still, Harding was able to give us a few clues as to what will go down in tonight's season finale, which picks up after the Liars were arrested at the end of last week's episode. Look forward to seeing "a really extravagant set, the girls wearing lavish dresses, and a cage," Harding revealed. "There's something that they go to investigate, and then they're led into a trap and kidnapped."

Pretty much, it's business as usual in Rosewood---and as always, the last scene in tonight's episode will give you some serious chills. "The final shot pulls back to show them in the middle of the woods," said Harding. "And it looks pretty horrifying."

Although we weren't able to squeeze much out of him about the finale, Harding did reveal five personal things about himself during our chat. Scroll down to find out what we learned.

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1. He didn't know what a hashtag was until he watched the show---and now he's a pro at coming up with them."I remember the exact moment of seeing the bottom of the screen say, #WillEmilyStay, or something like that, and I had no idea what it was," Harding said. "I was like, 'Is the TV broken?'" After a co-worker reassured him that all was okay, Harding picked up the art of the tweet quickly. "I like to make up my own now, like #EzraHomeless," he said. "People are always like, 'Oh my god, what does that mean?'"

2. One of the show's most infamous scenes was actually a fan's idea.The writers often take suggestions from fans, such as the scene in which the Liars' significant others posed wearing nothing but Santa boxers in this year's Christmas special. "The writers were like, ‘Let's give something back to the fans,'" said Harding of the shirtless moment. "I had to stand there next to Keegan Allen, who was eating a pizza as I was having celery for the 85th time."

3. In an upcoming independent film, Harding plays an Uber driver---but he's never taken one himself."The movie is set entirely within an Uber, so I was literally inside a Prius for three days," he said of the yet-to-be-titled feature. "I'm the driver, and you think it's going to be this romantic comedy between me and this girl that I pick up, but then the guy who's in the car with us turns out to be a sociopath." Things turn dark pretty quickly, and, spoiler alert: "I end up dead in a swimming pool," Harding revealed.

4. He's raised over $40,000 for the Lupus Foundation of America, a cause that's close to his heart."My mom has lupus, and we've raised all of this money entirely from fans---it's amazing," Harding said. His efforts to increase awareness about the disease included selling a t-shirt with his face on it, the proceeds of which went to the foundation. "The fans love it and are so supportive---they've done a lot to help raise money."

5. Surprise! He likes to birdwatch."It’s just my jam," Harding said. "The most expensive app on my phone is the Sibley Bird App." He played one of the app's birdcall sounds for Team InStyle, and said that when he uses it, "All of the birds start flying, and I'm just like, 'Fly, my pretties!'" Having an educational hobby? Total Ezra move.

Check out the preview for tonight's season finale below, and tune in to ABC Family at 8 p.m. to watch.