Songfacts®:

• In this ominous tune, the sisterly duo behind the indie-pop band The Pierces warn us about the consequences of divulging secrets. After murdering her loose-lipped sibling Allison, Catherine Pierce learns an important lesson about trust: "Two can keep a secret if one of them is dead." Catherine borrowed the sentiment from Benjamin Franklin, who's credited with a similar quote.
  
  She told Songwriters On Process: "I was sitting at a restaurant and saw a guy with a T-shirt with a Ben Franklin quote that said, 'Three can keep a secret, if two of them are dead.' And I thought that was so interesting. I changed it for our song, which says, 'Two may keep a secret if one of them is dead' to make it more personal. But there was also something happening in my life that went along with that quote. A group of my friends was having trouble keeping secrets; everyone was revealing everyone else's secrets at the same time. And I thought about how no one really keeps secrets anymore."
• This was the only single released from The Pierces' third studio album, Thirteen Tales Of Love And Revenge. The album, produced by Roger Greenawalt (Nils Lofgren, Rufus Wainwright), marked a sonic departure for the duo, who ventured away from their folk-rock roots into edgier territory. According to Allison Pierce, it came together almost by accident.
  
  "We just wanted to have fun and experiment. We didn't even go into the studio planning on making an entire record, because we hadn't signed to a label," she told Bullz-Eye in 2007. "We'd just gotten out of our Universal deal, and we met this guy named Roger Greenwalt, and he said, 'Come by my studio – I have a studio in my apartment – and we'll record a couple of songs.' And, actually, we did that with another friend of ours, John Kent, who lives in Texas. So we just slotted all that together, and we had a great time in the studio, and we realized what great chemistry we had with each other, as far as recording goes. So we just started doing it as often as we could. He did it in his free time, and we would end up going over three or four times a week and just having fun. We would bring him a song, and we would say, 'Okay, what fun things can we do with this song?' And we would do it. It was pretty magical, because we just got to do whatever we wanted. We were like little kids in a candy store or something."
• The Pierces sang this when they appeared in the Gossip Girl episode "Hi, Society" in 2007.
• This became famous as the theme song to Pretty Little Liars, a teen drama that ran on ABC Family/Freeform from 2010 to 2017. Based on a book series of the same name, the show followed a group of girls who are tormented by an anonymous villain that knows all of their secrets. While filming the first season, Ashley Benson, who played Hanna Marin on the series, heard the song and suggested it to showrunner I. Marlene King.
• A version by Denmark + Winter was used as the theme song to the short-lived Pretty Little Liars spin-off Pretty Little Liars: The Perfectionists in 2019.
• This was also used in the 2009 comedy ExTerminators, starring Heather Graham and Jennifer Coolidge.
• To commemorate the 10th anniversary of Pretty Little Liars and the 13th anniversary of Thirteen Tales Of Love And Revenge, The Pierces released a new version of the tune in 2020.