Their first gig will be at the Unite Against Hunger special charity banquet on November 9 in Johannesburg. Two days later the band will perform with Motown diva Diana Ross at the Bellville Velodrome in Cape Town.

On November 13 Westlife will hold a concert with South African Idols contestants at the Altech Grand Prix at the Kyalami Grand Prix Circuit, north of Johannesburg. The band then head to Bloemfontein for a concert at the Callie Human Hall, University of the Free State, on November 21 in support of the Unite Against Hunger charity.

It will be Westlife's first time in the city. The band, who recently scored a number one spot on the British charts with their new single You Raise Me Up, went on a five concert sell-out tour of South Africa in February.

Songwriter for "You Raise Me Up"

Westlife are back on track after a long stint out of the limelight. Today the group’s album will debut at the top of the UK charts, thanks to their new hit single.

But while You Raise Me Up may have given Westlife its 13th No 1, the real winner is the Irish novelist and songwriter who wrote it. Brendan Graham, 60, from Tipperary, has seen more than 100 artists record the track since he penned it in 2001, notching up an estimated 15m sales and earning him about €1m in royalties. Now Westlife, who sold about 200,000 albums last week alone, will add considerably to Graham’s retirement fund.

“I’m trying to work out what I did,” he said. “This is the pension song, as they say. At this game you don’t get a pension, so one needs the odd song like this. It’s fantastic.”

Louis Walsh, Westlife’s manager, was generous in Graham’s praise. “It’s all about the song — that’s actually selling the album,” he said. “It’s got something that just captures people. It’s going to sell millions and their album will sell millions worldwide too.”

The band members are modest about their input. “Without a doubt 80 to 90% of it is down to the song,” said Kian Egan. “We are back with a big bang. If we had come back with a plain pop song, I don’t think we would have got anything like this reaction.”

Westlife are the 103rd artists to record the anthemic ballad. As well as versions by artists in Ireland, Britain and America, the song has been recorded in Spanish, Italian, Portugese, Swedish and Norwegian and there are several Asian translations.

“The variety is quite interesting. It has been picked up by classical artists, pop and everything in between, including country and gospel,” said Rolf Lovland, a Norwegian composer who co-wrote the song with Graham and splits the royalties. “The last one was a disco version.”

Lovland originally wrote the music for You Raise Me Up for Secret Garden, his own musical act with Fionnuala Sherry, an Irish violinist. They won Eurovision in 1995 with an instrumental track, Nocturne.

Lovland asked Graham to write the lyrics for the melody after reading the writer’s first novel, The Whitest Flower, set during the great famine. “Brendan wrote some very powerful words to it — it was a piece of genius work he did,” said Lovland. Brian Kennedy sang on the Secret Garden version, a No 1 hit in Norway.

It was this record that David Foster, an American record producer, heard and decided to give to his protegé, a 22-year-old pop opera singer called Josh Groban. Groban’s version topped the Billboard adult contemporary chart for seven weeks, and was nominated for a Grammy. It was released as a single from his album Closer, which sold 6m copies.

Foster, in an RTE documentary last year, described the track, which has echoes of traditional Irish airs such as Danny Boy, as “darn near a perfect song”.

Selah, a US band, had a No 1 in the Christian charts with their version last year. The track has been adopted by religious congregations of all denominations across America for use in services.

It is being used in trauma and cancer recovery programmes and in anti-bullying courses. It is one of the most used songs at weddings, but is also one of the most sung at funerals.

“People see the song in different ways; some as a love song, others as a spiritual one,” said Graham. “In America it has taken on the mantle of a patriotic song.” Both American presidential candidates wanted to use it in their election campaigns but Graham has a clause in his contract that says his work can’t be used in politics.

Graham became a full-time songwriter after losing his job in the clothing industry in 1993. The following year his song Rock’n’roll Kids, sung by Charlie McGettigan and Paul Harrington, won the Eurovision. In 1996, Eimear Quinn won the song contest with Graham’s composition The Voice.

That year he began writing novels after landing a publishing deal with HarperCollins. The third book in his trilogy will be released this week and features Graham’s most famous song in a central scene, in which a confederate soldier sings it to a young Irish nun.

Among those who have recorded the song are Daniel O’Donnell, and Tommy Fleming, who is two places behind Westlife in the Irish album chart with Voice of Hope, which also contains the track.