Britney Spears is getting serious about her comeback - she's shooting a top secret video in Los Angeles. The Toxic singer has reportedly sworn her aides, friends and backing dancers to secrecy about the project, but word has spread the video will be for new song Get Back. Spears launched a mini-comeback in May (07) when she toured House of Blues venues in America with a puzzling series of 15-minute lip-synced concerts. The new video will be the first Spears has shot for two years.