ABC Family has picked up 12 additional episodes of Pretty Little Liars, three weeks into the newcomer’s promising freshman run. That brings the show’s total first season order to 22 episodes. Pretty Little Liars launched as ABC Family’s No. 1 series debut ever in several key demos, including adults 18-34 (837,000), viewers 12-34 (1.7 million) and teens (904,000). Additionally, the show has been growing, posting its most-watched episode yet last week in Total Viewers (2.7 million) and delivering series highs in the 18-49, 18-34 and 12-34 demos. Based on the Harper Teen novels by Sara Shepard and produced by Alloy Entertainment and Warner Horizon, the hourlong series stars Troian Bellisario, Ashley Benson, Holly Marie Combs, Lucy Hale, Ian Harding, Bianca Lawson, Laura Leighton, Chad Lowe, Shay Mitchell and Sasha Pieterse. I. Marlene King, Oliver Goldstick and Leslie Morgenstein executive produce.