Rolf Harris and the Fron choir announced their collaboration in Llangollen on Wednesday
Rolf Harris is to re-record his 1969 Christmas number one hit Two Little Boys to help mark the 90th anniversary of the end of World War I.
An emotional Harris, 78, has told how he recently discovered that his father and uncle had fought alongside each other in France and Belgium.
He has teamed up with north Wales' Froncysyllte Male Voice Choir for the remake of the battlefield song.
It was the top-selling single in 1969 and was number one for six weeks.
The 60-member Fron choir, with an average age of 67 are based near Wrexham. They reached number one in the classical charts with their Voices of the Valley album.
The artist and singer's contribution presence takes the combined age of those on the single to 4,025.
You'd think after 90 years it wouldn't affect you so much, but it really does
Two Little Boys is believed to have been written in 1902 and tells the tale of two boys who once rode wooden horses together, then ended up on a battlefield.
The song, which was the Christmas number one in 1969, was once named by Margaret Thatcher as one of her favourites for its theme of loyalty.
Harris cried as he recalled how he recently filmed a BBC documentary about his family's role in World War I.
Wiping back tears, he said: "You'd think after 90 years it wouldn't affect you so much, but it really does."
He said recording the documentary, Family at War, had made the lyrics to Two Little Boys even more poignant. He said: "I went across to Ypres in Belgium and then into France.
"I was following the footsteps of my father and his brother who were from Wales - they came from Merthyr originally. I was in floods of tears most of the time in the filming, just hearing about the losses. My dad and his brother were there.
"It had never occurred to me that Two Little Boys could relate to that. When we came back we got in touch with the Fron choir."
Welsh voices: The Fron choir with Rolf Harris, who has family roots in Merthyr
He said the original version was the biggest selling record for EMI in 1969 and was the last number one of the sixties.
He added: "I think it's time for another one, what do you reckon?"
The choir was "discovered" at a wedding in 2006. Conductor Ann Atkinson said: "Any time Rolf wants to join the choir, he's there."
Talking about Harris's relationship with the choir she said: "The minute he met the guys he started singing and when he arrived last night for the rehearsal at Acrefair school he was off again the minute he walked in."
The choir's third album, Voices of the Valley: Home, will be released alongside the single on 10 November.
Daniel Glatman, former manager of boy band Blue, who manages the choir after first hearing them at a friend's wedding, said: "We feel honoured to record with a man of Rolf's stature.
"It's another sign of how far the choir have come in the last few years on their amazing journey."
The song was the biggest-selling single of 1969, staying at number one for six weeks.
Dennis Williams, one of the choir's founding members, said at the launch in Llangollen, Denbighshire: "I remember this song the first time it was in the charts.
"To record it now with the man himself is a dream come true."
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