Dear John(ny),

It’s time for an intervention.

As your latest marriage, to actress Amber Heard, collapses in ugly high-profile divorce after just 15 months, your moment of reckoning has arrived.

We don’t know each other, but I feel like I know you better than perhaps you currently know yourself.

The problem with being a movie star of such magnitude is that it’s often very easy to disappear up inside the self-adulatory bowels of one’s own ‘genius’.

I get it. As a movie star it’s easy to disappear up inside the self-adulatory bowels of one’s own ‘genius’. But you need to be careful as the ego can take control

We’re a year apart in age – you’re 52, I’m 51 - but we’re a world apart in every other way.

You look in the mirror each morning, and you see Johnny Depp, impossibly handsome, absurdly sexy, ludicrously gifted, hugely popular global star.

I look in the mirror each morning, and see Piers Morgan, sadly lurking at a slightly different end of the impossibly handsome, absurdly sexy, ludicrously gifted, hugely popular global star spectrum.

So I get it, I can see why it must be bloody difficult to be even vaguely normal when every man you meet wants to go for a beer with you, and every woman wants to go to bed with you.

The sheer volume of painfully sycophantic guff which must spew your way in every waking hour of the day would tip most of us over the edge of humility.

You go to Starbucks and everyone sighs, faints or just stands, glass-eyed and paralysed, reciting the words ‘It’s Johnny f**ing Depp!’ over and over like a demented love-struck robot.

But the problem with fame on your level is it often becomes poisonously corrosive.

It takes your soul and crushes it into a broken slab of deadened vacuity.

When you can have sex with whomever you like and party with your fellow louche heroes like Keith Richards, Marilyn Manson and the late Hunter S Thompson whenever you desire, the fun of real life ceases to exist.

No more thrill of the chase, no more joy in the quiet, solid friendship of somebody non-famous.

I remember when you played the older, LSD-addled Thompson in the movie of his iconic book, Fear and Loathing in Las Vegas, and he told you after seeing it, “it was like an eerie trumpet call over a lost battlefield.”

That’s going to be you, Johnny, if you’re not very, very careful; an aimless bugler looking back with nothing but regret for what he should and could have done to win the battle of life.

I’ve no idea what happened between you and Amber, and I don’t care.

After your estranged wife Amber was charged for smuggling your dogs and she escaped with a $1000 fine and a one-month ‘good behaviour’ bond, you mocked the Aussie judges with this apology video, rather than just being eternally grateful. You're a couple of fakes

It’s your marriage, your business.

But I could sense it was doomed from the moment I saw that pathetic video you released after the now infamous dog-smuggling case in Australia.

Your joint thespian egos conspired to secretly bring your Yorkshire terriers Pistol and Boo on your private jet into a country which has had big problems with rabies.

The punishment for ‘normal’ people in such cases is rightly draconian: a heavy fine and prison sentence of up to ten years.

After Amber was charged with various offences, you joked you’d killed your dogs and eaten them ‘under direct orders from some kind of sweaty big-gutted man from Australia.’

Despite this appalling, justice-mocking arrogance, she escaped with a $1000 fine and a one-month ‘good behaviour’ bond.

Rather than be eternally grateful to Australia’s star-worshipping judges, you instead chose to mock them again by filming a self-promoting parody apology with Amber.

I didn’t find it funny.

I just saw a pair of insincere fakes being insincere fakes. Carry that theme into a marriage and the words ‘happy ever after’ seem highly unlikely.

What I did laugh at, though, was your ridiculous voice.

You were born in Kentucky and raised in Florida. Where the hell did that absurd, slow-talking baritone drawl come from?

And where did that ridiculous drawl come from? You're from Kentucky! You think you're your hero Brando, as Don Corleone. But remember Brando got old and bloated and was a thrice married loner

Oh yes, I know: your hero, Marlon Brando, in the Godfather.

You want us to think you’re Don Corleone because it doesn’t get any cooler in your eyes than being Don Corleone.

But here’s the problem, Johnny: you’re getting less and less cool by the day.

‘I’m kicking 50 right up the a**,’ you declared just before you arrived at your half century.

But instead, it appears that entering your 50s is kicking YOU right up the a**.

Your ‘look’ - the old battered fedoras, rotting leather jackets, stained and duct-taped jeans, skull rings on the fingers, myriad tattoos and dishevelled goatee – is now so tired I want to give it a pillow.

Your looks, once so fiercely fresh and youthful, have turned the way they usually do when a man hits our age: puffy and middle-aged. You’re still way better looking than me, but you’re not the Adonis you once were.

You’ve morphed into Mickey Rourke light, without the facial scarring.

As for your acting, you’re still very good as you recently proved in the excellent Black Mass, but you’re not, I fear, as good as you think you are or as you once were.

Off camera, I suspect the problem is simpler: you never stop acting.

You told Rolling Stone magazine last year: ‘Covering myself in makeup, it’s easier to look at someone else’s face than your own. Jesus, you wake up in the morning and you brush your teeth and you’re like, “Ugh, that f**er again? You’re still here? What do YOU want?” Hiding, I think it’s important. It’s important for whatever’s left of your sanity.’

Your looks, once so fresh and youthful, have turned puffy and middle-aged and you’ve morphed into Mickey Rourke light, without the facial scarring. Here you are earlier this week. You're a father. You're 52. Act like it

Then you solved the mystery of that ridiculous voice, revealing that you constantly hear Brando’s own voice in your ear, growling, saying: ‘F**k it, you don’t need this s**t.’

But remember what happened to Brando; he became a fat, bloated, weird loner who married three times, fathered 16 children, and ended up being driven by Michael Jackson around the singer’s Neverland fantasy home in an oxygen-stocked golf cart.

That way madness lies, Johnny. Utter, self-delusional, narcissistic insanity.

Don’t do it to yourself.

Be better.

There comes a time in every buccaneer’s life when you have to stop being a pirate.

A time when the cutlass has to be put back in its sheath, the eye-patch discarded and the favoured refrain of ‘Yo, ho, me hearties!’ as you plunge into yet another debauched Vegas-style orgy is finally confined to the vault marked ‘Gloriously Debauched History’.

You’re a 52-year old father of two now, it’s time to behave like one.

Find your voice again, Johnny. Your real one, whatever that is.

In fact, go one better: find yourself again.

Stop running, stop hiding, stop slapping on that make-up to mask who you really are.

Otherwise, you’ll end up not just sounding like a sad old Marlon Brando tribute act, but being one.