Preview Clip of Pretty Little Liars Season 3, Episode 13: The Little Liars Get a Musical Surprise (VIDEO) Tweet October 9, 2012 at 03:27PM EDT by Rebecca Martin Related: Pretty Little Liars, Sneak Peeks , Music , Aria Montgomery , Hanna Marin , Spencer Hastings , Emily Fields , Season 3 , Season 3 Episode 13 Credit: ABC © 2012 Disney ABC Television Group via YouTube Air date: October 23, 2012. The Pretty Little Liars Season 3 Halloween episode (Season 2, Episode 13: ”The First Secret”) is just a few weeks away (it airs on Tuesday, October 23), and this new sneak peek should make you more excited than ever.In this clip from the episode, the Liars walk into a Halloween bash (it's on a train, 'cause why not) only to find American Idol star Adam Lambert performing "Cuckoo" — and yes, it's really Adam! Surprise!
)
