Growing up in south Wales, Sir Tom Jones always knew he wouldn't have to follow his father down the mine, thanks to his extraordinary talent for singing.

And as he reflects on his life for a new BBC documentary, the 85-year-old says he knew he was lucky. "I was born with a voice. I don't think you can create that," he says. "That's what gave me the confidence. I was always confident as a child, because I could always sing."

But even with that self-assurance, never in his wildest dreams did the working class lad from Pontypridd think he'd end up performing alongside the likes of Elvis Presley, Little Richard, Aretha Franklin, Janis Joplin, Chuck Berry and Jerry Lee Lewis, to name but a few.

Interviewed earlier this year for BBC1's In My Own Words arts strand, Sir Tom also opens up on the death, in 2016, of his wife of 59 years Linda, and on how his son Mark became his manager in the 1980s - and ordered him to 'ignore the underwear'.

Viewers will see archive footage of Sir Tom being brought a cup of tea by Linda while gardening at their brand new first home on the Manygate Lane Estate in Shepperton, Surrey, where he had film-stars including Diana Dors as neighbours.

"My wife, myself and my son used to live with my mother-in-law in Wales, so this was very special, this place. I bought my first car as well, a red Jaguar 3.8," he recalls, saying that Linda was "thrilled to bits" to have her own kitchen and a bathroom, rather than a tin bath nailed to the wall. It even had a portable bar, "which we thought was very posh at the time".

His womanising over the decades is the stuff of legend - Tom has told previously of sleeping with up to 250 groupies a year at the height of his fame, and one liaison ended with him fathering a child.

But he and Linda married at the age of 16 after she became pregnant, and they stayed together until her death, from cancer, in 2016. During that time they spent a lot of time apart, because he was often on the road while she preferred to be at home in Los Angeles, where the family moved in 1974, staying for decades.

He talks about feeling emotional while recording his cover of the Bob Dylan song What Good Am I in 2010, when Linda had become unwell. "I was thinking of my wife, she was in my mind when I was recording it. Her health wasn't good, and mentally, she wasn't in a good place and I felt partly responsible for it," he admits. "So I felt 'what good am I, if I'm just like the rest, if I just turn away, when I see how you're dressed'. Because she'd lost it, you know. So that was on my mind when I recorded it."

The singer said that his wife had urged him to carry on with his career once she had gone. "When she passed away I said, 'Linda I don't think I'll be able to carry on' and she said 'you must carry on, that's what you do, you're a singer you've got to carry on, don't let this destroy you'."

Sir Tom said that he always knew Linda loved the real him. In one archive clip he explains simply: "I know my wife married me for me because I was nobody at the time."

Having moved to London from Wales, his first single on the Decca label flopped, but he was determined to do better with the second, despite his manager, Gordon Mills, telling him he couldn't have the song It's Not Unusual because it was destined for Sandy Shaw. "When I heard it back I said - 'that's the song'," he remembers. "'No,' he said, 'it's for Sandy, it's a nice bossa nova-type thing'. I said, 'Look, if I don't get this song I'm going back to Wales because I know this is the one'." In the end, of course, Tom won, - and the song went to number one on 1 March 1965.

That was the year in which he first met Elvis, with whom he'd remain friends until the latter's death in 1977. "I had a ballad out then called With These Hands. So when I met Elvis Presley on the set he started to walk towards me singing With These Hands, my song. I thought 'if the boys back home could see me now'."

A string of hits followed for Tom, but despite his regular residencies in Las Vegas by the late 1970s he'd started to go off the boil after failing to get a foothold during the disco days. Instead was persuaded into lots of BBC variety specials from locations including Switzerland and Barbados, which he calls "fluff". "I wasn't getting the hit records so what do you do?" he says now. "Other people were getting hits all through the disco era and I didn't get one of those songs, so I had to rely on TV to keep me in the public eye. You've got to take the rough with the smooth, but it was taking me away with what I really want to do musically. It was fluff. I wasn't particularly comfortable with it, but I didn't really have a choice."

Slowly he started to turn his career around again, helped in part by his son Mark becoming his manager and trying to remind fans that he was more than a sex symbol, an image perpetuated for years by his tight trousers, gyrating hips and open shirts. "The songs were not coming so I was concentrating on live shows and I think I might have become larger than life," he concedes. "At this time my son and daughter-in-law were my managers and made me aware, you know, don't pick up the underwear! If they're going to throw it at you let it land where it may, but don't make a big deal out of it because you're belittling yourself, you're cheapening your talent. And they were right."

A big change came for Tom when he recorded a cover of Prince's Kiss with the Art of Noise in 1988, and it flew. "It was like starting over," he says. His resurgence continued throughout the 90s, when he continued to work with younger artists, bringing him a whole new audience. This success was cemented with the Reload album, in which he duetted with the likes of Stereophonics, Robbie Williams, Van Morrison and Cerys Matthews.

He feels that being a shock addition at Glastonbury in the legends slot on the Pyramid stage in 2009 was another masterstroke. "When they asked me to close the event as the surprise guest I thought, 'we'll go there and do a soulful show' - but the result was unbelievable," he laughs. "I'm still here, that's how you feel. I'm still here, I'm doing it, I still love it - and thank god the people still love me doing it. You can't ask for more than that."

In that same year he decided to stop dying his hair after watching a clip of himself on Later with Jools Holland and not liking what he saw. "I thought 'my god, my hair, it looks dyed - and permed!'" he declares. "Well, it wasn't permed but the dye made it look more like that. I thought this is not working, it looks false and I don't want to be false." He stopped, and everybody loved him him as a sliver fox. Sir Tom, who remains dedicated to his mentoring role on ITV's The Voice, said he loved making the BBC film. "Some of the archive I'd not seen before and watching snippets of those past times, places, styles and struggles brought home how lucky I am," he said afterwards.

Having enjoyed a career which has lasted since the 1960s, amassing him a fortune thought to be well in excess of £100million, the Welsh singer says that the highlight of it all was receiving his knighthood from the Queen in 2017. "She was so lovely," he remembers.. So looking back, he has no regrets. "Not really," he smiles. "I wanted to be a professional singer and I've done that. It's a wonderful feeling."

Tom Jones feels 'partly responsible' for wife's mental health issues before she died - The Mirror