“Take me, for instance. I have six of them, and that means that at any given time I can have two of them very mad at me, but if the other four are happy, I’m still in good shape, because four out of six is a great batting average!” At last he gives up his struggle with the straight face and roars with laughter. Once the wildest of Hollywood wild boys, Don Johnson has calmed down considerably over the past two decades, and it clearly suits him.

Married and divorced four times before he was 50 – two of those marriages having been to Melanie Griffiths, after first dating her when she was still only 15 – he ricocheted along the way from affair to affair with women ranging from groupie Pamela Des Barres, to actresses Patti D’Arbanville and Cybill Shepherd, to Barbra Streisand, no less, to nearly 30 years younger actress Jodi Lyn O’Keefe, who played his daughter on the TV show Nash Bridges.

All that changed, however, in 1996 when he went to a party and met San Francisco socialite and nursery school teacher Kelley Phleger.

Reportedly, he shoved her then-boyfriend aside and informed her that he was going to marry her. Certainly he made good on that plan in 1999 when the two wed in a quiet but exclusive ceremony in the San Francisco mansion of millionaire Gordon Getty, presided over by the mayor of San Francisco and with actor Robert Wagner as best man.

Twenty years later, he says, they are still as happily in love as on the day they wed. Which is impressive, as 20 years counts as a lifetime in a place like Hollywood. “It’s a long time anywhere, baby!” he chuckles.

“It helps that the woman I am married to is a saint. Really, she is. “I’ll have my little freak-outs here and there, and she doesn’t freak out at all, she just very calmly says, ‘Yes, I understand that that upsets you,’ and then she… well, she treats me like the toddler I’m behaving like! She takes care of the toddler, gets me calm, gives me my little cookie or my pacifier, and then we get along with life. We manage very well that way.”

Between six children, his and Kelley’s three, Grace, Deacon and Jasper, his daughter Dakota from his marriage to Melanie, his son Jesse from his relationship with Patti, and his stepson Alexander Bauer, Melanie’s son whom he raised while they were together and still regards as a family member, life in the Johnson household is never dull.

“We mix and we match and we all come together, and there’s the inevitable time when this sibling is arguing with that sibling, and this one isn’t talking to that one, and you just have to wait till it all blows over because by the end of Thanksgiving, or whenever it is, we’re together, they’re all best friends again!

“We have big dinners and we get out the musical instruments, the guitars and the ukuleles and the pianos and the drums, and we all play music together and it’s a hoot. It’s the craziest thing, and it’s just fun, fun, fun.”

He confesses that as a parent, he is easier on his younger brood of children than he was on their elder siblings. “You get softer when you get older. Parenting your first child, you’re just scared to death that you’re going to make a mistake. The second batch comes along and you’re like, ‘Yeah, whatever’.”

It’s obvious that, at least in Dakota’s case, no harm has been done by Dad’s earlier stricter attitude: she has followed his footsteps into the profession, where she has carved out a successful career of her own, along with hitting the headlines for her steamier-than-steamy love scenes in the controversial film trilogy Fifty Shades Of Grey.

Although Don is fiercely proud of his daughter and fully supports her right to make whatever professional choices she decides on, he says that, as far as family viewing went, this was one he decided to miss. “I said to her, ‘I wish you well but this is one movie I won’t be seeing.’

There are some images you just don’t need to see because I don’t want them in my brain. I don’t want to see bodies strewn on the highway after a shooting either. It’s hard enough to know that that stuff is there without having to see it. Not that this compares with the Fifty Shades films in any way… although if you’re a father, it kind of does!” His own acting career, which he admits has seen its share of ups with Miami Philip Michael and downs, is, happily, on an upswing right now. He can be seen on Sky TV playing a police chief in the acclaimed US superhero drama series The Watchmen.

And this week he hits the big screen playing Jamie Lee Curtis’s upper class wastrel husband in Knives Out, a tongue-in-cheek murder mystery with some surprising twists in the tail. From police chief to playboy is quite a character swing and that, he says, is how he likes it.

“I do have to work a lot because I have all the kids, but I think that by and large I’ve been very, very lucky – and, yes, astute – in keeping my career from being stuck playing a certain type of character or in a certain type of genre. I’m pretty proud of that over the five decades that I’ve been doing this. Show business is a funny thing and it certainly isn’t all sunglasses and autographs, but I’ve had an incredible career and I think I’ve been very fortunate.”

The man who first grabbed our attention as maverick cop Sonny Crockett in the Eighties TV series Miami Vice, will turn 70 on December 15.

And he confesses that is something he looks forward to with mixed feelings.

“I didn’t really think about turning 60 much, but this is a milestone – especially considering that I never ever thought that I would even get this far.

“But I’ve had a big life with lots of experience and lots of living and I’m looking forward to the party that I’m sure is being cooked up for me by my kids and my family because it’s a special time.

“I don’t feel any different from when I was younger, though. Well, not apart from the normal little new aches and pains that you feel when you get up in the morning – ‘Huh, that’s a new one. What’s that? Oh, yeah, I’m nearly 70.

“Other than that, I still feel the same way I always have. Sixteen years old and unruly!”