At 82, Andy Williams explains to Andy Welch why he’s still likes to perform twice a day, six times a week.

"Not a lot of people have their own theatre,” says Andy Williams, sitting in the dressing room of his Moon River Theatre, Branson, Missouri, sounding thoroughly contented.

“And you want to know the best thing about having your own theatre? When you build it, the dressing room is the way you want it. I’ve got large paintings on the walls, Warhols and things like that. It’s like a penthouse apartment.

It’s got a garden, a bedroom and a kitchen in it. Oh, and a couple of bathrooms. It’s quite something.”

The singer currently performs in the theatre, named after one his most famous songs, twice a day, six times a week. He might be 82 this December, but the original American Idol, just one of his many nicknames, doesn’t want to slow down just yet.

“Twelve shows a week is slowing down for me,” he says, grinning. “I’m only working four months this year, September to the end of December, then I’m taking time off until next September when I’ll start again.

“I’m planning on playing a lot of golf and travelling,” he says, adding that London “for the shops, galleries and museums” and Italy “for the driving” are his destinations of choice these days.

There’s a new compilation out in time for Christmas, The Very Best Of Andy Williams, as well as an autobiography, Moon River And Me.

Having spent the best part of the last year writing the book and, more recently, approving the tracks on the album – songs such as Music To Watch Girls By, Moon River of course, Up, Up And Away, The Impossible Dream and the enduringly popular Can’t Take My Eyes Off You – Williams’ legacy is very much at the forefront of his mind.

“There was a list of songs sent over to me that were going to be on the album, with a note asking me to flag up anything I would rather not be on there, but I like them all,” he says proudly.

“There are few things that weren’t hits in the US, but were in Britain, so they’re on there.”

Williams’ singing career began all the way back in 1938, when he, along with his three brothers Bob, Don and Dick formed a quartet simply called The Williams Brothers. Managed by their dad Jay, they travelled around American radio stations performing before being signed to MGM Studios in 1943 and appearing in a number of films. They teamed up with singer Kay Thompson four years later and found even greater, worldwide success until they parted ways in 1951. “I was thinking about that time with my brothers and Kay while I was writing my book,” he says.

“Definitely some of my happiest times.”

In 1962, he had his breakthrough single Can’t Get Used To Losing You and his series, The Andy Williams Show, which became part of American TV for the next decade.

During the Sixties and Seventies, Williams was a regular fixture in the casinos of Vegas, and recalls a meeting with Frank Sinatra.

“One thing definitely sticks out from that time, when I was having dinner with Frank and about eight people one night. Two of the people were Lucille Ball and her husband Gary Morton,” he says.

“We were sitting there with Frank telling his jokes and we were all having a great time. Some drunk at the next table spilled a glass of red wine all over Gary and this new suede jacket he was wearing. Frank suddenly changed entirely, and he got Jilly, his right-hand man, to take the guy outside and break his nose.

“I could never understand how a guy could be so tender and gentle and great when he’s singing his ballads, and still have that side to him. It was really odd, but that was Frank and he was a great friend of mine, and I still think he’s the greatest pop singer ever.”

■ The Very Best Of Andy Williams is out now. Moon River And Me: The Autobiography is also out now.