It is shortly after midday and more than 1,000 Muslims are gathered for jumu'ah - the Friday prayer held weekly at the London Central Mosque in Regent's Park.
But, as the call to prayer echoes over the loud-speaker, the worshippers catch sight of an unfamiliar figure picking his way through the prayer mats.
Rabbi Dr Shmuly Yanklowitz is at the mosque as part of a innovative project bringing together Muslim and Jewish entrepreneurs involved in running or developing social-action projects.
It is fair to say that he is experiencing an initial nervousness. "Everyone was aware that I was wearing a kippah; they were all noticing it," he says. "That was the largest group of Muslim men that I have ever seen. I felt both the excitement and energy of the experience and a little bit of fear, as a religious Jew, being in a room with a thousand Muslim men."
The 35-year-old rabbi and social activist, from Chicago, is one of 25 Jewish and Muslim entrepreneurs, from the US and Europe selected to take part in the Ariane de Rothschild Fellowship at Cambridge University.
The group are on their fifth day of a 12-day visit to the UK, designed to strengthen their business skills and promote cross-cultural dialogue to encourage ties between their communities.
It is not his first visit to a mosque, but he reflects: "I live with constant videos reminding me of threats that the [Muslim] community pose to me.
"But then I'm also aware most Muslims mean me no harm, but you can't help feel an element of fear when you're around a big group like that."
As the imam delivers his sermon on the importance of "promoting peace and respecting the sanctity of human life", Rabbi Yanklowitz listens intently.
"I even recited a few Hebrew words myself and it felt very comfortable," he says. "It felt like a house of God. There is the rocking and moving and the focus is on individual thought and prayer, much like a shul.
"It was a highly positive experience, but I do wonder if that is a really typical message or were they aware there was quite a large group visiting."
Attending the intensive two-week programme at Cambridge, the rabbi and his peers learn how to develop their organisations and strengthen the impact of their projects.
Rabbi Yanklowitz, who is the founder of Uri L'Tzedek, an Orthodox social justice movement, explains that, "for me, it is less about understanding each other's theologies and more about working out how we can work on things together."
By taking part in the project, the rabbi has been able to meet Umar Hakim, a black Muslim who grew up in Compton, a deprived and gang-ridden inner-city area of Los Angeles.
Mr Hakim beat over 500 applicants to be part of the programme, which, since its creation in 2009, has developed 158 leaders across the world.
He is the director of the ILM Foundation, which founded Humanitarian Day in Los Angeles - an initiative similar to Mitzvah Day in the UK - in which, during the month of Ramadan, Muslims volunteer to feed the homeless.
Mr Hakim explains: "I'm here to develop a way my organisation can keep running on the business side and still make a difference, but then I've also been able to speak to Rabbi Yanklowitz about race.
"We have talked about how, I as an African black man, have experienced racism. How often do you get to have that conversation between a Muslim and a Jew?"
The 44-year-old, who converted to Islam in 1998, says the Rothschild programme has helped "build a safe space to share values and exchange ideas".
He adds: "We now have a network we can rely on to help build our expertise. If each of us represents say, 10 people, and you multiply that by how many of us there are, you have a whole bunch of people who are going to feel the impact of this project."
The Fellowship was founded by Ariane de Rothschild and Firoz Ladak, respectively president and executive director of the Edmond de Rothschild Foundations, which provide the funding for the scheme.
According to Reima Yosif, the programme's global co-ordinator, the founders "wanted to come up with a way to bring people from Jewish and Muslim backgrounds together, but not necessarily address interfaith". Participants, or Fellows, work on a business plan and get expert advice from Cambridge University professionals.
"Alongside that, they work on dialogue skills," she continues, " and how to think about 'the other,' which in business is key for negotiation, not just interfaith."
Manouchehr Shamsrizi, a Fellow of the project and founder of a tech start-up, hopes the programme will help him advance a video game he has developed to help dementia patients.Mr Shamsrizi, who describes himself as "Persian" and who lives in Germany, says: "An illness like that does not distinguish between your faith and your background and that is why I'm here.
"We need to develop a different version of the game for every different culture, be that in Tel Aviv or India.
"Meeting entrepreneurs who are from other cultures is a great way to learn about them and make that happen."
Marc Green, head of fundraising at Leo Baeck College in London, hopes the time spent on the two-week programme will help him develop a business plan that will lift the college from "just getting by… that's what happens every year and we're too good to just get by. Long-term strategic planning is not done in Jewish charities and that has left us in doom.
"We need to change that. So, to have two weeks where I can sit down and put together a strategy and business plan that I can take back to my board of trusties is invaluable."
Following the mosque visit, the group attend a Shabbat service at New North London Synagogue. Like Rabbi Yanklowitz at Regent's Park, Iranian-born participant Hamoon Ekhtiari admits to some nervousness:
"Not having ever been to a synagogue, I was excited and anxious at the same time," the 30-year-old says.
"While I struggled with the security and turned a few heads based on how I look, two experiences stand out: listening to an exceptional young woman eloquently make the case for women's rights by drawing on Jewish teachings as part of her batmitzvah ceremony and, second, having the opportunity to learn from the wisdom of Rabbi Jonathan Wittenberg as he welcomed us in his home for Shabbat dinner.
"Through these experiences, I gained a new appreciation of the way Jews build community."
The shul visit was a big moment for Noor Toshani - at 21, the programme's youngest Fellow. The Libyan-born social entrepreneur, who is working on an online platform to help Muslim women find jobs, reveals: "Until now, I had never met a Jewish person before. But I did not feel out of place at all. People were so friendly."
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