"High School Musical" star Zac Efron turned awestruck fan on the red carpet at the Oscars on Sunday afterbumping into "Avatar's" Sam Worthington.

The young actor couldn't resist cooing about the sci-fi movie on live TV after meeting the Aussie for the first time.

Efron told E! cameras, "I saw it ('Avatar') four times; I've seen you (Worthington) in 3D, regular, HD - I've seen you in every 'D' possible... You are the man, dude. It's great to see you."

A red-faced Worthington joked, "That's the easiest $100 I've ever paid... It's all good."

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