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Just last year, Isabelle Allen was playing the lead (as a boy) in a production of The Pied Piper of Hamelin at her school. Tonight, the 10-year-old actress will attend the star-studded premiere of her first big movie, Les Miserables.

ET's Christina McLarty caught up with the young thespian (who portrays the younger version of Amanda Seyfried's Cosette) at Dylan's Candy Bar in New York City, her first-ever visit to the Big Apple.

Video: Stars of 'Les Mis' Singing Live on Set

In preparation for the night's big premiere, Isabelle reveals she picked out a special dress for the occasion to make her feel like a princess.

"It's a white dress and it's got a netted skirt with little bits of sparkles in it and a bow," said the young actress proudly.

Co-stars Hugh Jackman, Anne Hathaway, Amanda Seyfried and Russell Crowe are expected to join Isabelle on the red carpet Monday, and as it turns out, the burgeoning star tells ET she forged great relationships with everyone on set.

Related: Anne Hathaway Didn't Eat For 13 Days Filming 'Les Mis'

In particular, Isabelle says she loved spending time with Hugh who, during breaks, would help her sharpen her craft.

"I got lots from Hugh," she said. "We do a lot or running scenes from Javert so [he taught me] how to look really tired."

Watch the video for more!

Les Miserables opens Christmas Day.