More from EW
1 of 12
At the inaugural Teen Choice Awards in 1999, both pop tarts were reflective. Spears faced the cameras in pailette-covered pants, while Aguilera accessorized her shiny leopard print mini-skirt with a gold coin belt.
[polldaddy poll=6494928] Who looked better?
2 of 12
At the 10th Annual Billboard Music Awards in 1999, Spears looked ready for the prom in a lavender gown and white pashmina, while Aguilera looked ready to party in a sheer skirt and midriff-baring T-shirt.
[polldaddy poll=6494931] Who looked better?
3 of 12
Both ladies tried on more grown-up looks for the 2000 Grammy Awards. Spears' sexy halter gown was more polished, but Aguilera took home the trophy for singing talent.
[polldaddy poll=6494932] Who looked better?
4 of 12
Then 18 year-old Spears was the talk of the night when she ripped off her tear-away tuxedo to reveal a nude bodysuit at the 2000 MTV Video Music Awards. Aguilera's red leather two-piece was also hot, but did you see Britney's nude suit?!
[polldaddy poll=6494941] Who looked better?
5 of 12
Perhaps "Who was worst dressed?" is the better question here. At the 2000 Billboard Music Awards, Spears was big pimpin' in her ankle-length trench and feathered fedora, while Aguilera paired a boring white dress with stripper boots and skunky hair highlights.
[polldaddy poll=6494944] Who looked better?
6 of 12
Now that's more like it! At the 2002 Grammys, Spears rocked a simple red column gown and Aguilera worked a retro-inspired sheer sheath and finger waves.
[polldaddy poll=6494946] Who looked better?
7 of 12
The ladies wore matching wedding gowns when they joined Madonna onstage at the 2003 MTV Video Music Awards to perform "Like A Virgin."
[polldaddy poll=6494960] Who looked better?
8 of 12
The ladies used the spider web style to different effect at the 2008 MTV Video Music Awards. Spears' one-shoulder silver number was short and sexy, Aguilera's body-conscious gown was full-on glamourous.
[polldaddy poll=6494961] Who looked better?
9 of 12
The ladies both got the little black dress look right in 2009, with Spears showing off her trim figure at the Teen Choice Awards and Aguilera striking a chic pose at Variety's 1st Annual Power of Women luncheon.
[polldaddy poll=6494974] Who looked better?
10 of 12
In 2010, Spears struggled to recapture red carpet glory at the Grammy Awards as Aguilera hit her style stride at the Golden Globes.
[polldaddy poll=6494964] Who looked better?
11 of 12
At KIIS FM's Wango Tango 2011 concert, Britney ruined the look of her strapless frock with a pair of clunky boots. Aguilera's footwear choice for a press conference for The Voice looked downright dangerous.
[polldaddy poll=6494977] Who looked better?
12 of 12
This summer, Spears seemed comfortable in a sparkly beige dress while on tour with The X-Factor, but Aguilera struck a sour note in a layered ensemble at a press event for The Voice.
[polldaddy poll=6494979] Who looked better?