Pentatonix, the a cappella super singing sensation, are known for bringing their unique and beautifully harmonic takes on holiday staples. Their Christmas albums have achieved incredible success and their videos have been viewed by millions of fans.
From their bio:
Three-time Grammy® Award-winning and multi-platinum-selling artist Pentatonix (presently comprised of Scott Hoying, Mitch Grassi, Kirstin Maldonado, Kevin Olusola, and Matt Sallee) formed in 2011 during NBC’s The Sing Off. Shortly after winning NBC's a cappella singing competition the band separated from their record label and subsequently turned to YouTube to promote their debut independent releases. The Pentatonix YouTube channel currently boasts 18 million subscribers and has yielded more than 4.5 billion video views, including “Hallelujah" (500 million views), "Daft Punk" (325 million views), and "Mary, Did You Know?" (230 million views).
They brought their talent to the Christmas staple "God Rest Ye Merry Gentlemen." It's an old English Christmas carol whose roots date back to the 16th century and was later updated with lyrics inspired by Charles Dickens.