Christina Aguilera, Dan + Shay perform in Times Square for 'New Year's Rockin' Eve' (11 images)

Christina Aguilera and Dan + Shay perform in Times Square on New Year's Eve for Dick Clark’s New Year’s Rockin’ Eve With Ryan Seacrest on Monday. An estimated one million people attended in Times Square on New Year's Eve and over one billion watched throughout the world as the traditional Waterford Crystal ball brought in 2019.

Christina Aguilera performs in the rain on New Year's Rockin' Eve. Photo by John Angelillo/UPI

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Aguilera sings her 1999 hit "All I Wanna Do." Photo by John Angelillo/UPI

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Aguilera performs her hit "Ain't No Other Man." Photo by John Angelillo/UPI

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Aguilera last performed on the show in 2007. Photo by John Angelillo/UPI

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