Neils correct look at the website. I too am on Emirates to Dubai & Singapore & have spoken to their customer service. They confirm the pricing is a very strict 1 x 20 kg case UK- Dubai £25 per kilo excess rising to £35 pk for longer duration. We are limiting ourselves to 15kg each as any cheap deal bargains we purchase in the Far East could end up very costly on the excess baggage scales. Go to Emirates/plan & book/essential infomation/baggage. It's also worth checking with Princess to see if they have any dispensation with Emirates, don't hold your breath though. Regards Wilba.
Things change constantly with luggage so for a perfect answer look on their web-site, I wouls add that you are lucky if Princess have used Emirates because they give you more room than most other airlines. ....Neil.