Transcript for Prince George celebrates his 4th birthday

Let's move along, everybody. It's royal celebration as prince William and princess Kate return from the family's five-day tour of Germany and Poland. Just in the Nick of time for prince George's fourth birthday. That was really bad. Don't do it. I prefer you to start talking about sandwiches again. Adrienne is covering the festivities and newly released portrait of George breaking the internet. I think we'll break the internet. Yes, the duke and duchess of Cambridge William and Kate bringing along their two adorable children in what many called a charm offensive throughout Europe making pretzels, visiting the symphony and preparing to have a birthday party. New year, new George. This morning a brand-new portrait of the now 4-year-old pint-sized prince in commemoration of his birthday. There will be a party and the whole William and Kate country's estate. Reporter: The birthday boy and sister princess Charlotte stealing the show one last time Friday. Early birthday gift and an ecstatic prince George exploring two different helicopter cockpits with George. William showing his kids, the royal ropes, even helping George into a pilot's helmet. George's excitement a far cry from those sleepy faces earlier in the week not quite ready for the fun to end. Princess Charlotte makes a bit of a royal fuss before taking a tarmac tumble. Kate kneeling down to calm the 2-year-old before gracefully picking her up to board their flight home. William and Kate taking their children on a European tour was really about them. They wanted to be close to their children. Always when the past members of the royal family used to leave their children at home with their nannies while they conducted diplomatic business abroad. Earlier in the day the duke and duchess had fun of their own and William tries his hand on a cargo ship simulator reminded that he is the future kick but this te Kate takes charge as the navigator. Then Kate shows off her musical chops as conductor of the Hamburg symphony orchestra. ??? Kate and William especially Kate being praised for her showstopping fashion and new haircut and chopped about six inches affectionately being called the cob or the Kate Bob. I like that. I have a different kind of Kate Bob. You have a kob. Nothing worse than your child throwing a temper tantrum. They know when you're in public. No mercy. They have no mercy. But Royals are just like us. That's why we love William and Kate. They're just like us? Really? Kind of. Last time I was invited to conduct a symphony it went just like that.

This transcript has been automatically generated and may not be 100% accurate.