Mark Hamill Performed Dialogue From 'Batman: The Killing Joke' and Everyone Went Crazy

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The 'Star Wars' actor makes a pretty good Joker.

Mark Hamill sure knows how to impress a crowd!

Star Wars Celebration 2016 is currently underway in London, and Star Wars star Mark Hamill showed up to greet fans during a special Q&A panel on Friday.

WATCH: Mark Hamill and Daisy Ridley Back in Character for 'Star Wars: Episode VIII!'

Hamill, best known for his role as Luke Skywalker in the original Star Wars trilogy, decided to surprise those in attendance by reading a few lines from his upcoming role in Batman: The Killing Joke in his iconic Joker voice.

"Memory's so treacherous," he said in his ominous Joker voice. "One moment you're lost in a carnival of delights, with the poignant childhood aromas flashing to the yawn of puberty. All that sentimental candy floss. Next, it leads you somewhere you don't want to go, somewhere dark, and cold, and filled with the damp, ambiguous shapes of things you hoped were forgotten. Memories can be vile, repulsive little growths. Like children, I suppose."

ET's Ashley Crossan was at the panel, and captured Hamill's impromptu performance.

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The 64 year-old-actor finished the monologue with his signature Joker laugh and received a standing ovation from the crowd.

Batman: The Killing Joke hits theaters July 25, 2016.

Hamill will reprise his role as Luke Skywalker in Star Wars: Episode VIII. For more on Rian Johnson's Episode VIII watch the video below.