Serbia's Crown Prince Alexander II on his ties with UK
23 March 2011 Last updated at 09:45 GMT
If you think of royalty in Europe - Sweden, Spain or the Netherlands might come to mind, but how about Serbia?
The country, now a republic, still has a crown prince and princess from its days as a kingdom many decades ago.
The BBC's Mark Lowen went to meet Crown Prince Alexander II, and Princess Katherine of Serbia.