Move over Britney Spears, there is a new star performer in the family! When Britney's sister Jamie Lynn Spear's daughter Maddie Briann Alridge covered her auntie's Femme Fatale hit 'Up N Down' the other day, proud aunt Britney was quick to share her perfoemance with her fans! She tweeted a 30 second long video clip of Maddie's rendition, and all we have to say is watch out Britney, watch out!