Songfacts®:

• In the third single from their debut album, Pentatonix offers one solution to deal with life's problems: sing. They wrote the energetic track with Boys Like Girls frontman Martin Johnson and songwriter Sam Hollander (Train, One Direction). In a Songfacts interview with Hollander, he explained how it came together. "'Sing' was one of these ideas that is just so specific that I didn't have a concept of who could pull it off, but I kept singing the beginning of it and it felt like something," he said. "I went over to Martin's, we started 'shedding it, and then we got the session with Pentatonix. We brought it in the room and those guys jumped on and began writing with us and we pounded it out. We were using lots of Kevin's beatbox and lots of live stomps and claps and all that stuff. It was interesting to see it materialize production-wise.
  
  Martin finished the track and he really did a great job on both of those songs. I think they're absolutely beautiful. I hear 'Sing' a lot. People send me videos of show choruses at schools and stuff like that. That song still really moves me. I'm a big fan of optimism - sometimes with a little darkness interwoven - but that one is just pure bliss to me."
• PTX baritone Scott Hoying and vocal percussionist Kevin Olusola share lead vocal duties on the track. Hoying recalls trying to keep up with Martin Johnson's boundless energy: "He is the most energetic human being on the entire earth; he runs around the room and does like back flips. It's so full out, it's intimidating... He made me sing it over and over and over. But the song just came together so fast 'cos we were so inspired, and it really is just a celebration of what we do; sing, anyone can do it. And I am obsessed with that song; it's probably in my top three favorite songs on the whole album."
• Christian Lamb directed the music video, which shows the band cavorting with fans and features cameos by Maisie Williams, Hailee Steinfeld and Victoria Justice, as well as the YouTubers Tyler Oakley and Grace Helbig.