It was while she was performing at a fundraiser for The McDonald College that de León was discovered by one of the directors for the Cameron MacIntosh company. She appeared in two musicals in Australia mounted by the Macintosh company, "Miss Saigon" and "Rent". She stayed with the cast of Rent (where she was Christine Anu's understudy for the role of Mimi) and was dance captain for the musical, until being cast in "Hi-5" in 1998. She featured with a puppet named "Jup-Jup", voiced originally by co-cast member Tim Harding. de León and Jup-Jup's segment of the show, "Puzzles and Patterns", promoted and educated children on problem solving and mathematics.