Complex sentence: The first actor to join the cast of "The Lion King", Broderick learned of the role while he was on vacation in Ireland, where he received a telephone call from his agent informing him that the directors were interested in casting him as Simba.
Split into simpler sentences: The first actor to have been signed on to "The Lion King", Broderick learned of the role while he was on vacation in Ireland. He received a telephone call from his agent informing him that the directors were interested in casting him as Simba.