Former \"Dancing with the Stars\" professional dancer Julianne Hough is to return to the Los Angeles competition series as a guest judge, ABC announced. Hough, 25, will fill in for Len Goodman on the judges\' panel, alongside Bruno Tonioli and Carrie Ann Inaba, Oct. 7. ABC did not say why Goodman plans to be absent that night. Hough left the show in 2009 after five seasons to pursue a career as a country singer and film actress.