Inside Britney's 'Prison Mansion' - Can She Be Saved?

New fears for the erratic pop star emerge as she holes up alone and posts chaotic new dance videos

With her legs spread wide, Britney Spears hooked her thumbs into the sides of her bikini bottoms and gyrated uncontrollably, writhing along to the hit "Despacito" as it blasted inside her cavernous home. But as she stared into the camera, recording her moves to post on Instagram on April 21, her hyper-intense gaze "seemed far more unhinged than sexy or seductive," a source tells In Touch. "And she never seems to leave the house." Indeed, aside from the tropical vacations she takes every few months where she often poses for nude photos that also pepper her Instagram feed - Britney, 42, is almost always at home alone, says the source. And her increasingly bizarre behavior has sparked fresh concerns more than two years after a judge ended the conservatorship that ruled her life for more than 13 years.