Bella Thorne is standing behind Britney Spears as concern for the pop star has hit an all-time high. Thorne, 23, spoke to Fox News in an interview this week to promote her new single, "Shake It," released on Friday.The former Disney star also shared her take on the public's treatment of Spears after watching the now-viral documentary, "Framing Britney Spears." "It was so sad when I watched it," Thorne said of the doc.