Diana Donnelly is a model and former Miss Universe Ireland and is studying for a Masters degree in Business.
Her older sister Danielle is travelling with her boyfriend in Asia and is planning to meet up with Diana in China for Christmas. We spoke to both Diana and Danielle about their relationship.
"Danielle is loving and beautiful. I love her vibrancy and enthusiasm and I admire her wonderful sense of fun and imagination -- she always had fun games for us to play as kids.
"We are both creative but in different ways -- she is very artistic whereas I am musical. Even in fashion, she is more creative and I am more practical -- it's great because we can share clothes and style. The physical differences are mainly our colouring -- however we do look similar with our big smiles!
"There are almost four years between us and I think because of that the two of us were very independent of each other. However, we have always been very close. I know that the death of our sister Jill had a huge impact on us and has made us value and appreciate each other more as we have seen how short life can be.
"Time apart has also made our relationship grow and flourish -- Skype is fantastic!"
"Diana is such a beautiful person -- very honest and open. She can be blunt and to the point at times -- which is great when you need it, hard to take when you are not looking for it!
"She is also kind, sensitive and so loyal. She is a big softie at heart (I think we both get that from our dad!) I really admire her organisational skills -- her room and wardrobe are always pristine. She is also very practical and has a fantastic memory. If I lend her something, she will always give it back!
"Some of our best times together are the most simple. Like hanging out at home on a quiet night in, just the two of us -- we have such belly laughs together!"
Next week: Novelist Martina Reilly and her friend Irene