What episode of 'Dancing With The Stars' season 6 did Mark and Julianne perform together on the Results Show?

On April 1, 2008 (Week 3), Derek Hough injured his neck when practicing for a routine he and his sister, Julianne Hough, and their friend Mark Ballas were to perform to a live performance on that night's results show by Kylie Minogue of her hit song Can't Get You Out Of My Head. Derek appeared on the results show but Mark and Julianne danced the routine without him.