Princess Alexandra of Hanover, granddaughter of Grace Kelly, has announced news of her engagement to Ben Sylvester Strautmann. The pair have been together for a decade. Strautmann is a German former professional basketball player. Princess Alexandra displayed an 18-carat white and yellow gold diamond ring. The ring features a diamond. Sources confirm the couple plans to marry. The engagement follows a decade-long romance. Grace Kelly's granddaughter and the former athlete are now set to wed after more than ten years together.