<P> "Pilot" was written by series' showrunner and main collaborator I. Marlene King and directed by Lesli Linka Glatter . On January 27, 2010, ABC Family picked up the series for 10 episodes, set to premiere in June 2010 . The theme song for Pretty Little Liars opening is "Secret" by The Pierces, which was suggested by one of the show's stars, Ashley Benson . </P> <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>

When was the first episode of pretty little liars filmed