Mark Cann, 45
A retired Army officer, Cann is head of the Armed Forces fundraising charity the British Forces Foundation. He is also a polo aficionado, heading the Combined Services Polo Association, and is on the board of the Hurlingham Polo Association. He lives with his wife and children in Wiltshire
The chief of protocol at the White House was holding an Ambassadors Cup [polo tournament] in America in 2006. He's a Texan and into equestrian things and he wanted to hold an event to bring all the Washington ambassadors to. We had mixed teams and I was the token Brit, while Nacho was our elite player. I had little idea of who he was; I just remember thinking he was so gorgeous that I'd probably leave my wife for him.
He was a wonderfully strong rider who hit the ball really well, and was very generous in his play, spreading the ball around. The polo social scene over there is hectic, and after the tournament we all went to a series of engagements – and we seemed to rub along well. I've worked a fair bit with stars, but I don't think I've ever seen so much female adulation. At one party, Nacho was mobbed by so many women that I strode up to him, kissed him on the cheek and said, "Darling, don't forget you promised me that back rub," before dragging him out of the room, for which I think he was grateful.
Some time after that event I was setting up a discreet annual charity polo game at [officer training academy] Sandhurst, which Prince Charles, Harry and William were coming to, and I decided to ask Nacho to play; it's since become a regular fixture for him. Harry and William were young men growing up, and I think Nacho helped them to be mature on the polo field and set an example. The first year, I remember having problems on the field with a very aggressive player who nearly tipped Harry out of his saddle; Harry was getting angry, but Nacho was great at saying, "Relax, Harry, just calm down."
I've since chased Nacho all over the field at myriad venues, but it's like having a kick-around with David Beckham; you can't get close, but it's great fun trying.
We've met each other's families and stayed over at each other's houses – though I once arrived to stay at his place in Florida only to discover he and his wife had flown off to the Oscars last minute, as Madonna's guest. Recently, I held a dinner party at my house in Wiltshire, and my sister was so starstruck she was telling Nacho everything about me just to keep the conversation going.
The polo world is full of egotistical characters, but the person who should have the biggest ego is the least affected. I'm determined to find a flaw!
Nacho Figueras, 33
Born in Argentina, Figueras is co-owner of the highly successful, US-based Black Watch Polo Team. Known as the David Beckham of the polo world, he is also the face of Ralph Lauren's Black Label and Polo fragrances. He lives in Florida with his wife and children.
We met by chance at a charity game, the Ambassadors Cup, in 2006. Mark seemed like a loyal, trustworthy guy and I saw in him someone who could be a good bridge to Europe. He got in touch after the event as he wanted me to come to a charity polo match that the princes were playing in at Sandhurst; I was happy to help as it was a good cause and it seemed a good way to play in England.
It was Mark who made the introduction for me to Prince Harry, and I ended up bringing him to America for the Veuve Clicquot Classic Cup, in New York, which he's played for the past two years. They were the most successful charity events I've ever had; Harry trusted me and I think Mark is the reason for that.
Mark and I started doing a few charity events together, and I've enjoyed playing with him. He's very brave and tenacious, but is he good? Well, he has spirit. Once he hit the ball so hard it gave me a black eye for several weeks; I had to postpone a Ralph Lauren shoot, which I think he felt guilty about.
I've been to many charity functions and you don't always feel the people are there for the right reasons, but I could see Mark did it with his whole heart.
It was polo that initially connected us but it has since became a very personal relationship: he has a beautiful house in the country and you can tell that family is very important to him, which makes us very alike – though at home you can see it's his wife who wears the trousers.
I didn't come from rich family, so I don't see polo as an elitist sport in the way some people do here. I was born in Argentina, which is a horse country. I want to make kids over here feel the way I felt when I was nine or 10.
I think Mark sometimes feels that he owes me a lot more favours than I owe him, but I don't look at it that way – yes, he asks for help, but the intention is good and it's always something I believe in.
The Gaucho International Polo event at the O2, London SE10, takes place on Thursday from 3pm. For tickets: theo2.co.uk