The personal picture of 34-year-old singer shows her wearing a pair of frilly pink knickers and covering her front with arms, reported Aceshowbiz.
The "Genie in a Bottle" hitmaker has clicked the selfie in front of the mirror of what looks like her bathroom.
Christina Aguilera celebrates 20 years of 'Genie in a Bottle'
"Just so you know with me, it's all real, all the time. Felt like it was time to start sharing some personal stuff with you guys... And it's just the beginning. Night night. X," she captioned the picture.