Joaquin Phoenix spent months watching videos of crazed laughter to prepare for Joker role

Joaquin Phoenix in The Joker. Photo / Supplied

Joaquin Phoenix's life has been as dark as any character he has played.

So it's hardly surprising that the actor is being praised for his role as the deranged Arthur Fleck in Joker.

Raised in an alleged sex cult and watched his brother die from a drug overdose on the street, Joaquin battled alcoholism before turning his life around, according to The Sun.

One Hollywood producer once put it: "There's a good reason he's good at playing traumatised. He was traumatised."

After landing the role in the Batman spin-off, Phoenix spent eight months studying personality disorders and even lost three-and-a-half stone for the role, which he admits made him "start to go mad".

THE SINISTER LAUGH

The character's laugh was formed through watching "videos of people suffering from pathological laughter," a rare neurological disorder.

He said: "I practised alone but I asked (Joker director) Todd Phillips to come over to audition my laugh.

"I felt like I had to be able to do it on the spot and in front of somebody else. It was really uncomfortable. It took me a long time."

Joaquin was raised by parents John and Arlyn Bottom and were in the hoppie cult Children of God until the Seventies.

The organisation has since been accused of encouraging sex between adults and children, and incest.

Joaquin, 44, originally named Leaf, said: "My parents were like a lot of people, searching for something.

"They thought they were going to be part of a group which shared the same ideals.

"Yet if one person gains power and becomes corrupted, it changes completely."

Actor River Phoenix during a 1988 photo session. Photo / Getty Images

In 1993, rising Hollywood actor and older brother River Phoenix overdosed on cocaine and heroin outside The Viper Room nightclub and died at the age of 23.

Joaquin called the ambulance, screaming: "He's having seizures! Get over here please, please, 'cause he's dying."

The actor dropped out of sight for a year following the tragic death.

But he returned within a few years as Roman emperor Commodus in 2000 film Gladiator.

He earned himself a household name before checking himself into rehab for alcoholism.

Joaquin Phoenix in "Gladiator". Photo / Getty Images

He said: "I just thought of myself as a hedonist. I was an actor in LA. I wanted to have a good time. I was being an idiot, running around drinking, trying to screw people, going to stupid clubs."

"There's too many things I enjoy doing and I don't want to wake up feeling hungover."

Joaquin's Joker film earned an eight-minute standing ovation at the Venice Film Festival.

Now Joker is being tipped for Oscar glory.