From PEOPLE Magazine Click to enlarge
Julianne and Derek Hough can turn any floor into a dance floor. At L.A.'s Pacific Theatres at the Grove recently, "we had 15 minutes before the movie began, so we literally just started dancing in the lobby," says Julianne. It was far from the first time. "We were back home in Utah and went to see Frozen," says Derek, "and before the movie started, we got the whole audience on their feet dancing."

Dancing has been the siblings' life for as long as they can remember, and it has come with its share of bumps and bruises along the way - some deeper than others. Their unconventional upbringing, including leaving home as children to turn pro, "really created strength," says Julianne, 25. She and Derek, 29, who eventually achieved mirror-ball glory on ABC's longtime hit Dancing with the Stars, are now teaming for this summer's Move Live on Tour. "We really want it to feel like a rock concert for dance," says Derek. "We want the audience moving."

Looking back, the two say their love of dance began as soon as they learned to walk. "If you look at home videos of us, we were always dancing. There was always music on," says Derek. Raised in a Mormon household by their parents, Mari Anne and Bruce, in Salt Lake City, the siblings performed at school and state fairs. "My dad would always tell Derek, 'No hip thrusts onstage!'—which I now think is so funny because he earns a living doing that," says Julianne.

Their careers took a much more serious spin when Julianne turned 10 and Derek was 13. Their parents, who were divorcing, made the tough decision to send the two ballroom-dance prodigies to the prestigious London dance school Italia Conti Academy of Theatre Arts, forcing them to leave their three older sisters and sheltered Utah life behind. "It was a very difficult time for our family," says their father, Bruce, who like their mom, Marriann, visited them periodically. "We didn't want them to have to choose between their parents, and they had a great opportunity in England." They moved in with family friend Shirley Ballas, a ballroom dancer and teacher, who says the Houghs "had the word 'star' on their foreheads." Shirley's son Mark, 28, attended school with them and later joined them on Dancing with the Stars. "With Derek, blood couldn't make us any closer," says Mark. "The same with Julianne."

The trio endured a grueling schedule that had them leaving the house every morning at 6:45, taking the subway by themselves and heading to school. "I remember one of my first days there I got off at the wrong train station," says Julianne. "I was just standing there thinking, 'Where am I?'"

After a long day of dance and academics they would eat dinner and then go back into the studio until 11 p.m. "It was hard," admits Derek. "There were moments when I just wanted to go and have fun."

For preteen Julianne, the mature world of ballroom dance felt incredibly awkward. "It was weird the first time I tried on one of my dresses and it had boob cups. I remember pressing the boob cup in and it would stay, because I was flat as a pancake." She would prepare for competitions by getting a spray tan and applying tons of makeup. "When I look back, I think it's so sad I have no pictures of me with a cute, bare, 10-year-old face." In an interview with Cosmopolitan last year, Julianne said she suffered mental and physical abuse while living in London but declined to say who abused her. When asked about those comments, Shirley says, "She was the happiest little child. She was never left alone. We were always present."

Julianne says when she turned 14, the homesickness really began to sink in. "You're going through puberty. It's like, 'What the heck is happening to my body?' I decided I wanted to go home." But after arriving in Utah, she found it difficult to adjust to a normal life. "It was a very mature world we lived in in London. When I came home and went to high school, I didn't know how to relate." After a short time she returned to London to continue her studies and then, at age 18, moved to L.A. to pursue her dreams. After twice winning Dancing with the Stars, she landed roles in films such as Footloose and Rock of Ages. She's also made headlines for her romantic ups and downs - after her two-year relationship with Ryan Seacrest ended last year, she's now happily dating hockey player Brooks Laich. Derek has been linked to actresses Nikki Reed and Nina Dobrev. The siblings try not to meddle in each other's love lives. "We've been there for each other, but we also know when to back off and give each other space," says Derek.

Today Derek and Julianne credit their success to their rigorous childhood. "When we were in Utah and felt sick, we could stay home from school. But in London, Shirley would say, 'Unless you're on your deathbed, you are going to school.' I think it gave me an advantage when I came out here. You have to hustle. I wasn't taking no for an answer," says Julianne. Derek echoes the sentiment. "People will say, 'How could your parents let you go off to do that?' I think it's great that they saw an amazing opportunity. That is the reason we are here today."