Footage has captured a community leader respectfully declining to shake the Princess of Wales' hand during a royal visit in West London.
Kate and William recently met volunteers at Hayes Muslim Centre who are helping to fundraise for families left homeless after the devastating earthquakes in Turkey and Syria.
A clip shows the pair arriving at the centre and removing their shoes as a mark of respect.
Kate covered her head with a scarf as the centre, which is a resource for the wider community providing cultural, sporting and educational events, is also a mosque.
They were greeted by local leaders including Imam Sufyan Iqbal, who shook Prince William's hand but when the Princess reached out, he placed his hand on his heart and bowed.
Kate then withdrew her hand and smiled, copying the gesture.
Although the Princess is seen shaking hands with another man, in some Islamic cultures, men do not greet women by handshakes.
Instead, they place their hand on their chest and bow, as a sign of respect.
At the centre, the couple were told £30,000 was raised by the local community, with £18,000 from the total collected in just two hours after Friday prayers.
Kate said: "It's sad that there's a need to do funding - it's amazing there are communities like this here raising (funds)."
Islamic Relief aid worker Salah Aboulgasem stressed the hardships on the ground in Syria and Turkey which he has visited regularly in the past four weeks, and how a Syrian schoolgirl died due to a lack of co-ordination.
He told William and Kate about the rescue attempts he had witnessed, saying: "They're hearing voices underneath and they're hammering at concrete - you're working but you know you're not going to achieve anything but you continue to do so."
The aid worker added: "Across the border we rescued a young girl, there was jubilation - a nine-year-old girl. We then put her into the ambulance waiting.
"For 45 minutes there was a road jam because there was no co-ordination - she died in the ambulance.
"And that just puts into perspective the absence of infrastructure and compounded struggle upon struggle, and the longstanding humanitarian crisis that exists in Syria."
During the discussion William asked if lessons were learnt from events like the earthquake, saying: "Do we get better and better at this so each time, unfortunately, one of these things comes along we're quicker, we're slicker, we get aid to places better - is there a learning process?"
Saleh Saeed, the Disasters Emergency Committee (DEC)'s chief executive, replied that his organisation was not just a "fundraising platform" but best practice was shared across charities so they learnt from each other.
The funds raised by the DEC, which include donations from the King, Queen Consort and William and Kate, are being used to provide emergency shelter, medical care, hot food, blankets, clean water and safe spaces for children in Syria and Turkey where many people still live in tents.
Before they left, William and Kate's origami skills were put to the test when they sat down with Dila Kaya, 14, and Lina Alkutubi, 15, who made around 700 paper cranes as part of a fundraising effort for earthquake survivors.
The Princess told them: "It must be great for you to do something - because you're so far away," and Lina replied: "It was a really great experience. Everyone was so devastated, so this was really important."
The pupils, from Waldegrave School in Twickenham, south-west London, had partially completed a pair of cranes and asked the royals to finish the work, with Kate describing her attempt as "a bit lopsided".
William said his effort looked "more like a digger" and, glancing at his wife's bird, quipped: "Yours has got proper airplane wings - a go faster crane."
