The 39-year-old singer and actress performed her version of "The Christmas Song" during Monday's episode of the NBC late-night show.
Aguilera wore a festive plaid pantsuit and performed the song in front of a decorated tree. She shared photos of her look on Instagram.
"Tonight on @latenightseth," Aguilera captioned the post.
Aguilera's version of "The Christmas Song" appears on her 2000 holiday album, My Kind of Christmas. Aguilera celebrated the 20th anniversary of the album earlier this month on Instagram.
"20 years of #MyKindOfChristmas," she captioned a throwback photo of herself performing.
Aguilera released her eighth studio album, Liberation, in June 2018. She released two singles, "Loyal Brave and True" and a new version of "Reflection," this year for Disney's live-action remake of Mulan.
Aguilera will celebrate her 40th birthday on Friday.