It was the reveal seven years in the making. If you spent your Tuesday nights between 2010 and 2017 glued to Freeform, you know the absolute brain-bending chaos of trying to figure out pretty little liars who is AD. We’d already been through the Mona Vanderwaal reveal. We’d survived the CeCe Drake (Charlotte DiLaurentis) era. But the final "Big Bad," the one pulling the strings during the time jump, felt different. It felt personal.
Honestly, the show was always a bit of a fever dream. Talking birds? Check. High schoolers with the fashion budget of a CEO? Always. But the mystery of Alex Drake—the identical twin of Spencer Hastings—took the cake for the most divisive moment in teen drama history.
The Reveal That Split the Fandom
So, let’s get straight to it. Pretty little liars who is AD? The answer is Alex Drake. She was Spencer’s British twin sister, a character we didn’t even know existed until the very final episode, "Till Death Do Us Part."
A lot of people hated it. They felt like it was a "cop-out" because there were no real clues in the earlier seasons. But if you go back and re-watch with a sharp eye, the breadcrumbs are actually there. Troian Bellisario, who played both Spencer and Alex, knew for two full years before the finale that she was the one. She had to keep that secret while playing "Spencer" in scenes where it wasn't actually Spencer at all.
Think about the scene where "Spencer" asks Toby for one last kiss while he’s grieving. Or the time "Spencer" is at the airport with Wren Kingston. Those weren't writing inconsistencies. That was Alex Drake infiltrating the group. She didn't just want to hurt the Liars; she wanted to be Spencer. She wanted the family, the friends, and the love that she never had growing up in the foster system in England.
Why Alex Drake Was the Ultimate "A"
Alex wasn't just some random villain. Her backstory is tragic, albeit totally soap-opera levels of dramatic. She was born at Radley Sanitarium (where else?) just minutes after Spencer. Mary Drake, their mother, sold Alex to a wealthy family in England because she needed the money to get out of the asylum. But Alex was "troublesome," and that family eventually dumped her in an orphanage.
She spent her life scrubbing floors and working in bars until she met Wren Kingston. Wren, being the chaotic guy he always was, saw her and thought he’d seen a ghost. Once he realized she was Spencer’s twin, he told her everything. He told her about Charlotte. He told her about the game.
The Motivation Behind the Game
Alex didn't start the AD game for fun. At least, not at first. After Charlotte was murdered, Alex wanted justice for the sister she had finally bonded with. She came to Rosewood to find out who killed Charlotte. But as the game progressed, her motivation shifted into something much darker: envy.
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- She envied Spencer's intelligence.
- She envied the bond between the Liars.
- She desperately wanted Toby Cavanaugh.
- She felt the universe had dealt her a losing hand while Spencer got the "perfect" life.
It's actually pretty dark when you think about it. She even had Wren shoot her in the exact same spot where Spencer had been shot, just so their scars would match. That’s commitment to the bit. Eventually, she even killed Wren and turned his ashes into a diamond necklace. Yeah. That happened.
The Clues You Probably Missed
If you’re still salty about the reveal, I get it. It felt fast. But the showrunners left little hints throughout Season 6 and 7 that pointed toward pretty little liars who is AD.
One of the biggest giveaways was the "dream" Spencer had while locked in the barn. She sees her mother, Mary Drake, who tells her a story. But Spencer’s hair is different. Her clothes are slightly off. It wasn't a dream. It was Alex visiting her.
Then there’s the watch. Spencer Hastings is a creature of habit. She always wears her watch. In several key scenes in the final season, "Spencer" is seen without it, or wearing it on the wrong wrist. Fans on Reddit were losing their minds over this at the time, and they were actually right. It was a subtle signal that we were looking at the twin.
How the Liars Finally Won
The ending of the show was peak Rosewood. Alex had kidnapped Spencer and Ezra (on his wedding day, no less) and was holding them in a massive underground bunker that looked like a suburban backyard. She was ready to step into Spencer's life permanently.
But she forgot one thing: Toby.
Toby realized something was wrong because the "Spencer" he was interacting with didn't recognize the book he gave her, and she didn't smell right. Seriously. He tracked them down, and in a classic standoff, he had to figure out which twin was the real Spencer. He asked the real Spencer to tell him her favorite poem from a book they shared. She did. Alex couldn't.
The game was over.
What Most People Get Wrong About AD
A common misconception is that AD stands for "After Death" or "Archer Dunhill." While the Liars thought it was Archer Dunhill for a while, AD actually stands for Alex Drake. It’s the most straightforward answer in a show that was rarely straightforward.
Another thing people forget is that AD was actually more successful than the previous A's in many ways. She managed to physically replace a member of the group without them noticing for months. Mona was a genius, and CeCe was a master manipulator, but Alex was a chameleon. She was the reflection in the mirror that wanted to jump out and take over.
The Aftermath: Where Are They Now?
In the final moments, we see Mona Vanderwaal in Paris. She’s running a doll shop. But in the basement? She has Mary and Alex Drake trapped in her own personal dollhouse. Mona won the game in the end. She became the ultimate keeper of the "A" legacy, proving that you can never truly outsmart the original.
Looking back, pretty little liars who is AD remains one of the most searched questions in TV history because it represented the end of an era. It was the "Goodbye, Rosewood" moment. Whether you loved the British accent or thought it was the most ridiculous thing ever filmed, you can't deny that it kept us talking for years.
Moving Forward With Your Rewatch
If you’re planning on diving back into the series, keep these things in mind to make the AD reveal more satisfying:
- Watch the eyes: Troian Bellisario plays Alex with a slightly flatter, more predatory gaze than Spencer.
- Listen for the slip-ups: Pay attention to "Spencer's" vocabulary in Season 7. There are moments where her phrasing is just a tiny bit too "International."
- Observe the mirrors: The show uses reflections constantly in the final season to foreshadow the twin twist.
The mystery of AD might be solved, but the complexity of the Drake/Hastings family tree is something that will probably require a PhD and a whiteboard to fully map out for the rest of eternity.
Next Steps for Fans
To truly appreciate the complexity of the AD reveal, your best move is to watch the Season 7 finale, "Till Death Do Us Part," side-by-side with the Season 1 pilot. Seeing how far the "A" game evolved—from simple text messages about secrets to full-on identity theft and underground bunkers—highlights the massive scale of the show's evolution. You should also check out the various behind-the-scenes interviews with Troian Bellisario, where she breaks down the specific physical cues she used to differentiate Alex from Spencer. It makes the performance significantly more impressive when you see the "method" behind the madness.