Engelbert Humperdinck is driving home for Christmas. Or at least he will be tomorrow when he leaves London after four days of gruelling interviews.

The veteran balladeer, 82, is promoting his first Christmas album in nearly 30 years. Tomorrow he drives to Leicester for an early festive celebration with his family.

"It's so accurate, a song like that. The song is so real," he says of Chris Rea's classic, chatting happily in a quiet corner on the 15th floor of the St Georges Hotel in central London.

The world-famous crooner has the tanned skin and slim figure of a much younger man. Only his poor hearing gives away his octogenarian status.

His wife Patricia is not with him and she will not be travelling to Leicester. At the couple's home in warm Bel Air, Los Angeles, she is being treated for Alzheimer's.

Humperdinck, who changed his name from Arnold George Dorsey, recently went public about his wife's decade-long battle with the illness, a battle that has seen him searching desperately for a cure.

He will return to LA for Christmas Day, which he will spend with her.

"My family has always been important to me," he explains. "At Christmas time, we celebrate together, but this year I can't come home to Leicester because of my wife's illness. Hopefully, when she is better, we will come and spend Christmas at home."

His wife's illness dominates the conversation but Humperdinck is overwhelmingly optimistic. The pair met over 50 years ago at a dancehall in Leicester, and were married in 1964. Now, she struggles to recognise his face.

The performer, known for his deep Roman-Catholic faith, credits prayer for preventing her condition from worsening.

"The reason I went public with her condition is because I do have great faith and I believe that the more people who pray, the more it forms a chain, a rosary of prayer.

"It comes down to the person who is suffering, the victim of the disease. I think prayer is one of the greatest healers around, more than medication."

He has been investigating alternative medicine, looking to India and Sri Lanka for herbal cures.

"I don't think you should rely on medicine," he declares. "I think you should rely upon herbal doctors, acupuncture and doctors outside the medical world, with different kinds and forms of treatment. I rely upon nature to provide the cure for my wife."

And he claims to have found success in electrical acupuncture, shock treatment he claims can form new stem cells.

"I think it's had a lot to do with the repairing of my wife's health," he says.

Still a formidable performer with a voice seemingly unaffected by age, Humperdinck has been forced to reduce his touring schedule to spend more time with his wife.

"It's hard to leave her," he says. "But she's in reliable hands. She has her carers and I have to work.

Humperdinck's sharp sense of humour and gentle swagger remain intact - even after 51 years in show business.

When he turns to discussing his fans, dubbed the Humperdinckers, he is fiercely defensive. Trolling, he says, has never been a problem.

"You do get a bad apple now and again, but that doesn't matter. You ignore that," he says, before chuckling to himself: "I don't get the bad apples."

Humperdinck may not be a household name among millennials - or those under the age of 30 - but he has impacted modern music in surprising and extraordinary ways. Damon Albarn tried to recruit him for his Gorillaz project and a recent album saw him collaborate with Elton John.

And Humperdinck keeps one eye on the changing landscape of popular taste.

He says Ariana Grande is a "talent beyond" and his dream duet partner, and happily explains his aspirations to appear on talent show The Voice, which he uses as a barometer of popular opinion.

"I like watching those shows because they present music that is of today's nature," he explains. "This is the way I keep in touch with what is going on in the modern world."

But as long as his wife's illness continues to consume his time, it could be a struggle committing to a television show.

"If they ask me, I will. But in the meantime I am content doing what I'm doing, because I have time to spend with my wife, rather than be out of the house for 24 hours in a studio."

Aside from faith and family, the third great love in Humperdinck's life is football, specifically Leicester City FC.

It is no surprise, then, that the sudden death of his team's chairman, Vichai Srivaddhanaprabha, touched him.

The Thai billionaire lifted Humperdinck's team from outsiders to Premier League champions, but died in a tragic helicopter crash at the team's grounds earlier this year.

"It's a tragedy. It was terrible, terrible. He was such a wonderful man," he sighs.

"They came to LA to play in a match over there, and I went over to watch them rehearse, I mean practice. Ah, I'm from show business, you see. I met all the team and had the trophy in my hands. Oh yes. It was my pride and joy. It was wonderful."

For now, Humperdinck plans to focus all his energy on caring for his wife, snatching time to sing for his fans when he can. And despite all this, he feels a deep sense of optimism.

"You can't sit at home and wait for things to happen," he says. "You have to be here." he adds, slapping the table top with the palm of his right hand.

"You have to be here talking to people. That's the way I am. I'm not tired of it. I love doing it, and I'm still very flattered that people still want to talk to me."

Warmest Christmas Wishes is out now.