Supercouple! New Superman Henry Cavill and Showjumper Ellen Whitaker

Riding around the ring at the International Horse Show at Olympia, showjumper Ellen Whitaker had no idea that she was being watched keenly by a handsome young actor on the verge of superstardom.

In fact, when Ellen, one of Britain’s top riders, was introduced to Henry Cavill afterwards, the name meant nothing to her.

‘One of the other riders asked, “What do you do, then?” ’ she recalls. ‘Henry said he was an actor. When the other rider asked, “Are you famous?”, Henry replied, “The fact you’ve had to ask that suggests probably not.”

This is the sort of conversation he is unlikely to have again. Last month it was  announced that the 27-year-old public schoolboy from the Channel Islands is to play Superman in a new Hollywood blockbuster earmarked for release next year.

Described as ‘the perfect choice to don the cape and shield’ by Zack Snyder, the director of Superman: Man Of Steel, Cavill has been plucked from relative obscurity – his biggest part yet was in the TV series The Tudors, though he appears with Mickey Rourke in Immortals, a big-budget film out later this year.

But as Ellen, 24, a member of the famous Whitaker showjumping family, remembers, his impact on her that night at Olympia was more Clark Kent than Man of Steel.

‘I’d just come out of a very long relationship,’ she says. ‘I do remember thinking, “What a good-looking guy” but when Henry bought me a drink and asked for my number, I thought, “No, I’m off men. Don’t go there.” I was a bit standoffish.’

But Henry soon revealed a determined side worthy of the superhero born on the planet Krypton.

‘He sent me a message on Valentine’s Day. I thought, “Gosh, he’s not going away easily” and we started talking on the phone while he was in Canada filming Immortals.

‘When I bumped into him again months later at an event in Dublin, he looked amazing – supermuscly and fit. We started going out shortly after that.

‘Usually good-looking men are tough-going but he is the complete opposite. He is very driven but in a nice, calm way. He couldn’t be further from the image of a tantrum-throwing Hollywood star.’

This is just as well. Any visitor to the Whitaker farm near Barnsley, South Yorkshire, needs a down-to-earth approach to take on board the eccentric arrangements. As Ellen talks, three dogs bound around the kitchen.

Outside are two alsatians, a bull mastiff and 40 horses, including her £855,000 stallion Locarno and a mare called Ximena, which she will ride at the 2012 London Olympics if, as expected, she is selected to represent Britain.

Henry’s crash-course in the ways of the Whitakers included the day he was told he was the new Superman.

‘Henry came up that night to celebrate,’ says Ellen. ‘We went to the local pub and played pool. One of the locals said, “Is this your new boyfriend, Ellen?” I said it was and introduced him. The guy then said, “What do you do then, young man?”

I said excitedly, “Henry’s going to be the new Superman!” Someone else said, “Oh, well done, boy” and that was it. It’s the biggest leveller ever living up here.’

The couple have both had setbacks in their careers, however. Henry was close to being cast as James Bond before losing the role, while Ellen suffered the heartbreak of seeing Locarno sustain an injury that ruled them out of the 2008 Olympics.

‘This is a tough, hard sport,’ she says. ‘I think that’s partly why Henry and I work so well together. We have a mutual respect.

‘I was a bit concerned the first couple of times he went to Hollywood. I thought, “He won’t want to come back to me.” But he’s not like that. He could have anybody in the world but he insisted he wanted me.'