Burger King and Domino's Pizza have joined McDonalds in pledging allegiance to Saudi Arabia's new crown prince, Mohammed bin Salman.

While McDonalds paid for a newspaper ad to announce its support (as I reported on Thursday), Burger King and Domino's have opted for a cost-free solution by posting on Twitter.

Both firms posted photos of the prince branded with their company logo. 

The tweet in Arabic from Domino's said: "We renew the pledge of allegiance and loyalty to His Highness Prince Mohammed bin Salman on the occasion of his appointment as Crown Prince of the kingdom."

Burger King's tweet said: "We ask God to reconcile and reward, and preserve those who rule our affairs for all that is good."

Pledges of allegiance are customary in Arab monarchies when a new ruler comes to the throne but Mohammed bin Salman is so far only crown prince (upgraded this week from deputy crown prince).

In practice, however, the prince runs the country because his father, King Salman, is 81 and thought to be in poor health. Numerous reports have suggested that the prince's promotion, which puts him first in line to the throne, is a prelude to the king's abdication.

Prince of Famine

Though viewed as a moderniser, the prince has also acquired a reputation for recklessness. He was the main driving force behind the kingdom's disastrous military intervention in Yemen where, according to the UN, millions are now facing famine. 

The eagerness of fast food chains to associate themselves with the Prince of Famine met a lukewarm reception on Twitter. At the time of writing, Domino's tweet has only 12 likes and 25 retweets. Burger King has done a little better, with 91 likes and 198 retweets. Several Twitter users, apparently underwhelmed by the momentousness of the occasion, posted replies enquiring about job opportunities with the companies.