From midriff-baring teen queen to X-rated Xtina to Old Hollywood-inspired glamour-puss, the mother of one has undergone more head-to-toe transformations than most.
Look back at some of her most memorable outfits and hairstyles in the gallery below.
M-I-C all the future stars in this pic? A pre-teen Aguilera donned a floral-print denim jacket (who didn't?) and dark blonde locks for a photo shoot with Mickey Mouse Club co-stars Ryan Gosling, Britney Spears, and Justin Timberlake. What ever happened to those guys?
Clad in a hot pink cardigan, Aguilera played the part of bubblegum pop star perfectly.
A wild Shakira-esque mane, belly button art, and a revealing lime-on-lime ensemble? God bless the '90s.
Flaunting her favourite accessory - a flat midriff - Xtina opted for a low-cut pink top, cropped denim, and less-than-flattering orange shoes for the Teen Choice Awards.
She's got the Midas touch! Aguilera rocked a bold gold leather halter top and cigarette pants for a Grammy Awards after-party. Think C3PO's hot kid sister.
Songs in the key of G-string? Aguilera flashed her undies - and a ton of skin - in this slinky cutout dress. Dark cherry-cola-hued highlights completed the racy look.
We don't know what she did to piss off her stylist, but they sure did get their revenge with this scary ensemble. An out-of-control platinum mane, shredded velvet curtains, and enough makeup to rival Tammy Faye made heads turn - for the wrong reason - at the Blockbuster Entertainment Awards.
Cover your eyes, kids. For the single Lady Marmalade, Christina Aguilera - shown with Lil' Kim, Pink, and Mya - channelled the Moulin Rouge with a sexy garter belt, red platform boots and matching corset, and some killer crimped hair.
Clothes? Who needs 'em? A platinum-locked Aguilera bared nearly all in garters, lingerie, and a feather-trimmed robe for her Lady Marmalade" performance at the Grammys. Voulez-vous couchez avec moi, indeed.
We do so hate it when moths get into our crop tops. Aguilera made a very goth newsie with her cobwebby top, black spiral-curled highlights, and newsboy cap at a Teen People party.