<P> ABC Family began casting for a Pretty Little Liars television pilot in October 2009 . Lucy Hale was cast as Aria Montgomery in the project, followed by Troian Bellisario as Spencer Hastings and Ian Harding as Ezra Fitz in November 2009 . In December 2009, The Futon Critic confirmed the casting of Ashley Benson as Hanna Marin and Shay Mitchell as Emily Fields, as well as the addition of Laura Leighton as Ashley Marin, Nia Peeples as Pam Fields, Roark Critchlow as Tom Marin, and Bianca Lawson as Maya . Mitchell had initially auditioned for the role of Spencer and then tried for Emily . The Hollywood Reporter also noted that Torrey DeVitto and Sasha Pieterse landed recurring roles in the pilot . The Alloy Entertainment website later confirmed that Pieterse would be playing Alison DiLaurentis and DeVitto would be Melissa Hastings, also mentioning the casting of Janel Parrish as Mona Vanderwaal . Initially, Alexis Denisof was cast to be Aria Montgomery's father Byron . In April 2010, the role of Aria's father Byron was recast with Chad Lowe, and Holly Marie Combs was cast as Aria's mother Ella . Jenna Marshall is played by Tammin Sursok . The actors who played Ian Thomas and Toby Cavanaugh in this episode were after replaced by Ryan Merriman and Keegan Allen, respectively . </P> <P> After the pilot was shot in Vancouver, filming for the rest of the series has since moved to Los Angeles . The series is primarily filmed at the Warner Bros. studio and backlot in the city of Burbank (near Los Angeles). </P> <P> The pilot was broadcast on June 8, 2010 . It was watched by 2.47 million viewers, scoring a 0.9 rating in the 18 - 49 demographic . </P> <P> "Pilot" was received with mixed opinions, although the series has gotten a more positive critique over its progression . Metacritic gave the pilot episode 52 out of 100, based upon 14 critical reviews . The New York Daily News gave the show a positive review, commenting that it "makes most popular vampire romances look anemic", while concluding, "Pretty Little Liars could go in several directions, including mundane teen clichés . It's got an equally good shot at making us care about these imperfect pretty girls ." A writer on Terror Hook has stated that "' Pretty Little Liars' gets off to a very promising start . Great production all around, the writing keeps the viewer on their toes, and the acting just reinforces it . The overall mystery of the show in the end is dark and unpredictable, even stepping into the slasher film realm ." The New York Post gave the show three out of five stars, stating, "OK, so we've established that there is no socially redeeming value in this series and that your kids shouldn't watch it if they are too young and impressionable . But if you can distract them enough to miss the first 15 minutes, the show isn't half - bad . Actually, it is half - good, if that makes sense ." The Los Angeles Times wrote that the series is "one of those shows that manages to mildly, and perhaps unintentionally, spoof its genre while fully participating in it, and that's not a bad thing at all ." </P>

When was the pilot of pretty little liars filmed