On May 13, 2011, T.R.H.s Crown Prince Alexander and Crown Princess Katherine of Serbia attended The Princes Ball II: A Masquerade Gala in New York City. The event was held at Cipriani and was also attended by Prince Phillip, Prince Alexander, Prince Peter, and Prince Dimitri of Serbia.
The purpose of the event was to raise money for Lifeline New York:
Lifeline New York works with the HRH Crown Princess Katherine Foundation to improve the health and welfare of all those in need in Serbia. The monies raised will help fight breast cancer, infant mortality, childhood blindness and provide food, healthcare and educational services for refugees.