Dork Diaries: Popstar (Dork Diaries #3) - Rachel Renée Russell

Nikki's school is holding a talent competition and Nikki can't wait to start practising dance moves with her BFFs and impressing Brandon, her crush, with her singing skills! But then Nikki finds out that her arch-nemesis, MacKenzie, is entering the contest too, and she's determined to steal the limelight from Nikki and her friends.