Nancy Sinatra: 'His voice could make peace in the world'

Is it nice being back in London?
Oh yes. I wish I could stay and have some fun, but I'm only over for a few days. We were driving through Kensington the other day where we took some great pictures when I was recording Nancy in London [1966]. It was very evocative.

What are your reflections on that 60s period?
Kind of carefree. When you're in your 20s you think everything's a piece of cake and life is going to last forever. Get up into your 70s and it ain't the same.

How does it feel to be celebrating your father's 100th birthday at the Palladium?
The great thing is that we're bringing him home to the first place he ever played here [in 1950]. My hope is that people who actually saw him in those days will want to come and see the show and relive the magic. And this time round the show is even more technologically advanced than last time out [2006].

There are a lot of shows that pay tribute to Frank Sinatra – what sets this one apart?
It's the only one supported by the family. It's the authorised one. We have the vault of archives and can contribute things that other people just don't have. It's Frank singing Frank, with a live band. It's the closest you'll ever get to the real thing. That's what separates it from everything else.

We all know the public image of Frank – what was he like as a private man?
Lovely, shy, quiet, normal. Just your everyday guy. I asked him to describe himself once and he said 'Frank Sinatra – American baritone'. He liked his alone time and his solitude, but also loved being with people.

What was his approach to his work?
He was a consummate professional who demanded the most from himself, the best. "I always owe the audience the best I can be," he would say. He knew his audience worked hard for the dollars they spent on the tickets. He also knew how much they wanted to be in the same room as him, which is why he travelled so much.

How do you feel when you hear his voice now?
Sometimes happy, sometimes sad, always grateful. If his voice comes on the radio and it's a sad song, sometimes I'll turn it off. Sometimes I don't want to deal with that pain again. When you lose somebody and grieve them, the idea is that you move on with your life. But we haven't been able to do that, and there's good and bad in that. You can imagine.

How aware were you as a child that your father was so famous?
I'm 74 now, and my early years were very simple. In New Jersey with two parents, my father went to work and came home. There wasn't anything abnormal or unusual about it. Later on, when there was real notoriety and fame it was a little different. But he was still a wonderful dad. I couldn't have asked for a better one. He would always tell us kids "you come first".

It's not every dad who has Dean Martin round for drinks
Dean was a wonderful man. Though not a lot of drinking – that's folklore. Dean was a golfer. He'd get up early every morning and go and play golf. He wasn't one to drink a lot. He created a persona – the public idea of him is one thing, but the real Dean was another. There was a trick to the drinking.

What was the trick?
You go somewhere, a party, whatever, and if you're offered a drink you say thank you, and you have a sip, but then you put it down on a table and walk away and talk to somebody else. And that's what they used to do. I don't want to spoil this legend that's out there, but it just didn't exist.

You must get asked this a lot, but do you have a favourite Sinatra song?
There are three albums that I love dearly – In the Wee Small Hours, The Concert Sinatra and A Swingin' Affair!. I also love the Colombia stuff [1943-1952], when he got nicknamed 'The Voice'. That voice to me is so pure, and so marvellous; it could make peace in the world if everyone could listen at once.

How will you mark his 100th on 12 December?
We'll likely be in Vegas, at the Wynn, where we have a restaurant. And we're going to try and organise a happy birthday toast to Frank around the world, so that everyone can raise a glass.

Sinatra at the London Palladium runs from 10 July to 10 October 2015