It is a relationship forged 40 years ago on Britain’s Salisbury Plain and the wilds of the Brecon Beacons.
As young men, Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces, and the King of Malaysia, Sultan Abdullah Ahmad Shah, met as officer cadets at the Royal Military Academy Sandhurst, Surrey.
As this picture shows, the pair endured all the rigours of the exhaustive training regime as well as the odd moment of relaxation and levity.
Dressed in British combat fatigues, Sheikh Mohamed beams at the camera.
Sitting back on his rucksack or bergen, meanwhile, the Sultan of Pahang, who was officially installed as Malaysia's 16th king on Tuesday, looks on a little more tentatively.
On Tuesday, Sheikh Mohamed offered his congratulations to the new King of Malaysia after attending his coronation in Kuala Lumpur.
The two friends have retained their bond after completing their time at the college passing out at the military college between 1979 and 1980.
Sheikh Mohamed was among the dignitaries who turned for a coronation steeped in tradition in the Malaysian capital on July 30.
The royal appointment was the second meeting between King Abdullah and Sheikh Mohamed in as many months.
The two leaders met at Qasr Al Watan in Abu Dhabi in June to discuss efforts to increase trade between the UAE and Malaysia.
The high-level talks focused on investment and development opportunities as well as broader regional issues.