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High School Musical fans probably wouldn't mind looking at Zac Efron the rest of their lives.

But the actor, 21, says he tires of seeing his mug plastered everywhere.

"I didn't want to be famous," he tells USA Weekend. "I get sick of seeing my own face around."

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"I used to get so frustrated," he goes on. "For a while, I felt like I was completely lost in celebrity-land. I didn't know how to handle it. Now I know that I have to plot where I'm going, when I'm going there and where the back entrance is. It's like I'm playing a giant game of tag."

Efron -- who just dropped out of the upcoming Footloose remake -- says his career is now at "a transition point."

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"My taste is changing. I'm growing up," says the star, who hopes his new comedy 17 Again (out Apr. 17) will help him "shift into adult material."

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"I'm definitely not the best actor in the world at this point," he says. "But hopefully, with time and effort and smart decisions, that will change."

Acting wasn't something he always wanted to do, he admits.

As a kid, "I played sports on weekends -- baseball, basketball -- and when I sucked at those, I started playing golf and ping-pong in the garage," he says.

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"After I lost interest, I started singing," he adds. "I was always singing to the point where my parents would shout, 'Shut up, Zac! Enough already!'"