Katy Perry announced the song on Twitter, posting a four-second audio clip of it on November 14, 2018, with the caption that she was "Bout to sleigh in an hour".

It opens with Perry decorating a Christmas tree in a festive living room before Santa Claus and animated characters from Rudolph the Red-Nosed Reindeer appear.

Perry and Santa, who is dressed in a striped bathing suit and Hawaiian shirt, then have a pampered Christmas, relaxing at a poolside and getting massages while the animated characters wait on them.

[10] Idolator's Mike Wass called it "cute, catchy and utterly adorable", and observed that "the perky bop is every bit as irreverent and fun as you would expect".

[11] Marina Pedrosa from Billboard said that "Perry's vocals are velvety as ever as she sings the festive lyrics, 'Just you and me / Under the tree / A cozy little Christmas here with you.

'"[12] Zac Gelfand of Consequence of Sound wrote that "Cozy Little Christmas" is an "appropriate step back and a deep breath" for Perry and "a simple, bubbly, holiday love song, serving as a respite after an otherwise tough several months.

"[13] Writing for MTV News, Madeline Roth praised the "bubbly bop" as "mighty cozy", adding that "this festive little tune will be a crowd-pleaser all around".

[14] In the United States, "Cozy Little Christmas" entered the Billboard Adult Contemporary chart at number 10, becoming Perry's ninth track to reach its top 10 and first to do so since "Dark Horse" in 2014.