In a move that has been cooking for some time , the Saudi king on Wednesday fired his nephew as his heir and replaced him with his 31-year-old son, the young prince Mohammed bin Salman From top royals and clerics to ordinary citizens, Saudis far and wide have pledged obedience and allegiance to their new future monarch.Bin Salman has been behind several economic reforms in the kingdom including the part-privatisation of Saudi Aramco. He led recent discussions with OPEC and in his new role as deputy prime minister, he will likely face a grilling over oil.In a remarkable show of loyalty, a veteran Saudi journalist even quit his 13-year job at Al Jazeera in Doha to bring his inner self more into harmony with his rulers' anti-Qatar line.Now even American fast food joints in the kingdom have declared their love for the Big Cheese.Soon after news broke of MBS' appointment, McDonald's Saudi franchise swore fealty to the new crown prince on Twitter."We pledge allegiance to His Royal Highness Prince Mohammed bin Salman, and swear loyalty and obedience on the Quran and the Sunnah of his Prophet, praying for Allah to safeguard our beloved kingdom's safety and security," tweeted the burger chain's account.Commenting on the thread, several tweeters tagged other fast food outlets, including Pizza Hut and Dominos Pizza, challenging them to do the same. This journalist has, however, detected a tinge of sarcasm.It is unlikely that the Saudi authorities would take measures against those who fail to follow suit, despite officially criminalising sympathy with Qatar and what one watches on television , but McDonald's royal move could make it the country's real burger... king.