After a string of relationships with actresses and models and two failed marriages he once quipped: “Instead of getting married again, I’m going to find a woman I don’t like and just give her a house.”

But in 1999 his relationship cynicism and Da Ya Think I’m Sexy? swagger went sailing out of the window when he met model Penny Lancaster.

Seven years later he went down on one knee at the top of the Eiffel Tower and asked her to marry him.

Sir Rod, now 75, admits he cannot believe how Penny, 49, changed that old heart of his and made him a devoted hubby.

He says: “I’m stunned that Penny has kept me around for 20 years.

“I am lost for words. They have not invented the words for how I feel about her. She is everything.”

Rod, who has eight children by five partners, credits Penny for helping him understand the respect that underpins a long and happy marriage.

The rocker says: “It took me a while to learn, because I have been a bit of a scallywag in the past.

“The most important thing is good manners, which is what I try to teach all my boys.

“You can wear the best suits in the world, look great and have the best carpet, but you still have to show manners.

“Open the door for a lady, stand up when a lady goes to the bathroom when you are having dinner – my boys do that.”

Sir Rod states humour is “very, very important”…and apparently so is not laughing at your husband’s fashion failures.

He says: “I am colour blind so when I get dressed to go out I have to check to make sure the colours all go together. Penny keeps me in line.”

Their strong partnership has helped Loose Woman star Penny blossom too.

Sir Rod says: “I gave her a lot of confidence. She does a lot of TV work now.

“When we first met she was just a shy little person who would not talk very much.

“I have instilled the confidence in her. I am sure she would tell you that. And she is here for me.”

Sir Rod and Penny were originally isolating from the coronavirus pandemic at the family’s Florida mansion but later flew home to Essex – where they have a pool and football pitch – with sons Aiden, nine, and Alastair, 14.

The star was due back in the US for a tour, now-cancelled, in July but is still hoping to tour Australia and New Zealand in the autumn.

Devoted dad Sir Rod has a daughter Sarah, 56, from a teenage relationship, Kimberly, 40, and Sean, 39, from first wife Alana Hamilton and Ruby, 32, from his relationship with Kelly Emberg.

The singer also has daughter Renee, 27, and son Liam, 25, whose mother is his second wife Rachel Hunter.

Sir Rod says he tries to keep his youngest boys grounded – but is clearly a bit of a soft touch.

He says: “It is difficult. It is a fine line between spoiling them and depriving them. I sort of go either way. Penny is much better than I am – I will give them anything.

“With the older kids I say, ‘You have got to do it yourself, prove to me you can earn your living’. And that is what they do.

“But the two youngest keep me young. I come home and I am tired, but they go, ‘Dad, let’s have a kick about’ so I turn the floodlights on.”

Rod is also a doting grandad to Delilah, eight, the daughter of Kimberly and her actor partner Benicio del Toro.

Sir Rod says of Delilah: “It is wonderful. I do not get to see her enough and she is a bit shy of me.

“She thinks that I am some sort of a lion with this hair. But she is gorgeous.

“I love all my kids. They are the most important thing in my life. I cannot get enough of them.

“It is hard rounding us all up and getting us all in one place. They always have plans and say, ‘Sorry Dad, can’t come, Fred is coming into town’, or something like that.

“So I say, ‘If you don’t come, it’s coming out of your inheritance. So they show up.”

The family rallied round after Sir Rod was diagnosed with prostate cancer in 2017. Two years later he revealed he had been given the all clear.

He says: “Just finding out is a terrible shock. Like every parent you go, ‘I am not going to see my children grow up or get married. That is it. I am gone here’.

“My first reaction, like most men, was stiff upper lip. I carried on touring because I felt fine.

“I had six weeks of treatment, five days a week radiotherapy. Once that was done I went out on tour and forgot all about it.

“You cannot sink into yourself, you have got to get up and get on with life. I wanted to help other people but I didn’t want to help until I was on the right side of it in remission.”

Explaining why he finally went public, Sir Rod said: “So many men ignore health problems, including my father who never went to the dentist and went to his grave with one tooth.”

He says of the intimate prostate examination: “So many guys are scared of going to the doctors…so I thought if I come out and say ,’I am not the first’ it will make guys go.

“It is a cruel disease as you do not get any symptoms. Cancer is horrible. But this particular strand of cancer, you do not know about it. I have regular check-ups, every six months.”

Sir Rod counts himself lucky with his marriage, health and incredible music legacy.

He says: “If I asked for any more in my wonderfully successful career I would be a greedy man.

“If it all ended tomorrow I would be very happy. I don’t want it to but it has just been tremendous thanks to all my lovely fans.

“But there was a point in my career where the image I was trying to sell overshadowed my vocal performances and my songwriting. Now it is the other way around.

“Lyric content has always been very important to me. I tried to be heard. It is the way I sing.

“I talk to my boys and say, ‘I just heard one of your rap songs.

“I haven’t got a clue what he is singing about. Tell me what he is singing about?’…and they go, ‘I don’t know’!” The singer is currently working on an album of country hits which he hopes will be as popular as his Great American Songbook series.

He says: “I love Johnny Cash, not just the country stuff, but the folk stuff too.

“If I can do for those songs what my voice did for the American songbook it might just give them a whole new lift.”

Daughter Ruby is in Nashville band The Sisterhood but Sir Rod says: “I think she is leaning a bit too far to country because she has a great soul voice too. Absolutely blinding…a little Janis Joplin.”

Sir Rod still has the same passion for performing and says: “I want people to feel that I have entertained, given 100 percent.

“When I came into the business at 19 I thought if this lasts six weeks I will save up and buy a sports car and then I will get the girls.”