Director Tim Burton was speaking to an audience about his upcoming Alice in Wonderland movie at the Comic-Con International event at the San Diego Convention Center when he asked if they'd like to meet the "imaginary friend" who follows him around.
Depp, who plays the Mad Hatter in the upcoming fantasy film, then walked on stage, causing the crowd to erupt into cheers and applause.
After the hysteria calmed down, Depp said into a microphone, "Hey. Happy to be here," before waving and walking backstage.
Fans were in for a further treat as Burton screened footage featuring Depp as his Mad Hatter character, before joking about the inspiration behind his unusual look: "John and I worked together many times, but he's never done a character with orange hair. We scalped (redheaded comedian) Carrot Top and took his hair... We realized once we got into it that we picked out every image from TV and cinema of red hair and it's quite a distributing thing -- from Bozo (the clown) onward."
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