Answer:
He’s full name is “William Arthur Philip Louis Mountbatten-Windsor”
Explanation:
Prince William's official full moniker is William Arthur Philip Louis, which we can all agree is literally just a bunch of first names strung together without a last name in sight. He is officially known as His Royal Highness Prince George of Cambridge and has the middle names, Alexander and Louis. But when he attends Thomas' School in Battersea, he is known by a different name - George Cambridge.
His Royal Highness Prince Charles Philip Arthur George, Prince of Wales, Duke of Cornwall, Duke of Rothesay, Duke of Edinburgh, Earl of Chester, Earl of Carrick, Earl of Merioneth, Baron of Renfrew, Baron Greenwich, Lord of the Isles and Great Steward of Scotland, KG, KT, GCB, OM, AK, QSO, CC, PC, ADC.