The `Dynasty` star was not surprised that Russell Brand and Katy Perry recently announced their 14-month marriage is to end because she thinks famous people in relationships with one another can find it difficult.
She said: "It was written in the gods! I don`t know either of them. It was sad about Demi and Ashton, though. Two actors together can be difficult. I was engaged to Warren Beatty but I was more famous than him at the time. The ego can be in play with actors, particularly when you are young."
While other famous marriages break up, Joan, 78, is still "blissfully happy" with her husband of almost 10 years, Percy Gibson.
She said: "I`m blissfully happy. Percy is the one. Isn`t it amazing that I would meet him in my 60s? He is the love of my life, my soulmate - he is kind, clever, funny and everything I dreamed of. We had been together for around six months when September 11 happened. We knew we had to be committed to each other. Forever. Respect each other and give each other space. And have separate bathrooms!"