Derek Hough and Julianne Hough
Derek Hough got his start on Dancing With the Stars when he was a guest instructor on Season 4 with his sister Julianne Hough and Olympic skater Apolo Anton Ohno. Derek officially joined the cast for Season 5 and went on to win five Mirror Ball trophies. NBD! Julianne started on the dance competition show on Season 4 and won the Mirror Ball with Apolo Ohno that same season. She was a dance pro on Seasons 5-8 and made guest appearances on later seasons.