Zac Efron recently talked to Tiger Beat about his HSM3 dance moves. "I've never danced so much! I showed up to rehearsals a few weeks late for the movie because I was working on a different project. It was the worst mistake of my life because I was thrown into a number of dances that were extremely difficult. I never thought I could accomplish anything like this, so I was a little bit intimidated, but after a few weeks of rehearsal, we got it done. He says that  "The Boys Are Back." was the hardest musical number they had to do. "I had to do the waltz with Vannessa. It's hard for me to take the lead. It was funny because Vannessa was taking the lead more than me!" Zac says.