Songfacts®:

• This Phil Spector-sounding song is an optimistic tune that was written by Clarkson with her frequent collaborator, the hit songwriter/producer Greg Kurstin. The lyrics echo the sentiment of Mariah Carey's ubiquitous holiday classic "All I Want For Christmas Is You," with Clarkson looking forward to spending Christmas with her new man after weathering a lonely season without a mate the previous year.
  
  The song was released as the lead single from the singer's first Christmas album, Wrapped In Red.
• This isn't the first time that Clarkson has covered holiday music. She recorded the Christmas songs "Oh Holy Night" and "My Grown Up Christmas List" on the compilation American Idol: The Great Holiday Classics. Also, the Texas native's version of "I'll Be Home for Christmas" reached the #93 position on the Hot 100 in 2011, and she lent her voice to Blake Shelton's "Cheers, It's Christmas" the following year.
• While the traditional pop-leaning soundtrack to the classic 1954 film White Christmas was her initial point of inspiration for Wrapped In Red, Clarkson used the holiday album as an opportunity to experiment with different styles.
  
  "I've been dying to make a Christmas album," she told Billboard in 2013. "I always get asked about what genre I'm in - 'Is this country or pop or rock, what are you?' And what's cool about making a Christmas album was, "Oh! There are no limitations! We can do whatever we want!"
• Kurstin was game to experiment and dug into the Vince Giraldi Trio's A Charlie Brown Christmas and A Christmas Gift for You From Phil Spector for ideas. Spector in particular influenced "Underneath The Tree," with Clarkson's vocals being reminiscent of Darlene Love's on on the 1963 album's "Christmas (Baby Please Come Home)."
  
  "I also called in all my toys," Kurstin told Billboard. To emulate Spector's Wall of Sound, Kurstin played vintage instruments like the mellotron and Chamberlin and miked them from a distance. Instead of using background singers, he had Clarkson record all the vocals herself. Clarkson, who used to sing in a chorus as a child, had fun being her own choir.
  
  "Blending is something I knew how to do from my childhood," she said. "Sometimes I'd have to do an alto instead of a soprano because they needed a bigger sound. But I've never had to do anything like this before - doing all my own backup vocals, essentially being my own choir."
• In an interview with Jay Leno, Clarkson explained that Kurstin wasn't too familiar with Christmas songs because he's Jewish. But ironically his heritage only adds to his credibility as a yuletide hitmaker, as many a Christmas classic has been penned by a Jewish songwriter, including "White Christmas" by Irving Berlin, "The Christmas Song" by Mel Torme, and "Rudolph The Red-Nosed Reindeer" by Johnny Marks. Not to mention Phil Spector, whose dense orchestral style inspired the sound of Clarkson's song - the Jewish producer was a Christmas fanatic and considered his 1963 holiday album the masterpiece of his career.
  
  Kurstin joined the ranks with "Underneath The Tree," which was named ASCAP's most popular Christmas song released in the 21st century in 2021.
• This was used in lots of Christmas-themed media, including these movies:
  
  All I Didn't Want For Christmas (2022)
  Zoey's Extraordinary Christmas (2021)
  The Princess Switch: Switched Again (2020)
  A Very Merry Toy Store (2017)
  Office Christmas Party (2016)
  
  And these TV shows:
  
  The Clash ("Christmas Special" - 2020)
• "Underneath the Tree" came together faster than most of Clarkson's songs - way faster, in fact.
  
  Asked on her YouTube series which song she wrote in record time, Clarkson didn't hesitate: "It was 'Underneath the Tree.' I was working with Greg Kurstin in the studio. I ordered sushi, and when it arrived, I had written it."
  
  Clarkson explained that writing holiday music comes naturally to her, partly because she's such a huge fan of the season. "I think because I really love Christmas, I write them really quickly," she said. "They feel good, because you can be a little cheesy, you know? You don't have to worry about being cool, which honestly, that's not a concern generally ever, because I'm not."