Monaco (CNN) -- A day after tying the knot in a civil ceremony, Monaco's ruler and his South African bride reaffirmed their union Saturday in a religious ceremony at the prince's palace. The event kicked off the second day of festivities in the small seaside nation of 33,000, where a holiday has been declared to celebrate the wedding of Charlene Wittstock, a former Olympic swimmer, and Prince Albert. The 3,500 guests -- which include 20 heads of state, fellow royals and a number of moguls and celebrities -- began to arrive hours earlier Saturday afternoon at the palace, the same place where one day earlier the couple's civil ceremony had taken place.
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NEW: The religious ceremony is held in the courtyard of the prince's palace
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NEW: The bride's wedding dress is designed by Giorgio Armani, design house says
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Prince Albert and his bride Charlene Wittstock also have dinner and fireworks planned
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They had a civil ceremony Friday at the palace, followed by a picnic and musical concert
Prince Albert formally became @placeholder's head of state following his father's death in 2005.