Britney Spears posted a full-frontal naked selfie to her Instagram, declaring in the caption: 'Free woman energy has never felt better.' The 40-year-old pop star shared the image - that. Britney Spears has driven fans wild with a full-frontal nude photo on social media. The Toxic singer, 40, is no stranger to showing off her body online, having posted dozens of snaps over the past.