But, as these pictures show, the troubled star who recently announced his retirement from acting, has suffered a spectacular fall from grace.
The 34-year-old star looked dishevelled and bloated when spotted partying in Miami Beach, Florida on Monday night.
Wearing a ladies' hairclip to tie back his scraggy hair and his chiselled jaw covered up with a long, bushy beard, Phoenix looked a world away from the handsome Roman Emperor Commodus in 2000 epic Gladiator.
Joining him at the Liv nightclub was brother-in-law Casey Affleck, director Brett Ratner, actor/singer Jamie Foxx and hip-hop mogul Sean 'P Diddy' Combs.
A source with close ties to the actor says worries are mounting for his health, sanity and well-being after a particularly troubled 2008.
After a spell in rehab in 2005 and his recent erratic behaviour, the actor is cutting an increasing bizarre figure on the Hollywood social scene. Earlier this year, Phoenix disappointed his Two Lovers co-star Gwyneth Paltrow and fans by snubbing the film's world premiere at the Cannes Film Festival in May and the subsequent premieres around Europe.
Since announcing he was quitting acting to become a full-time musician in October, Phoenix appears to have piled on the pounds and given up on his personal grooming. In recent weeks, Phoenix has been hitting the clubs and bars of Los Angeles with aplomb, prompting worries amongst his closest friends. The source said: 'Joaquin has rejected everything that has come along with Hollywood stardom, the acclaim, the attention, and the artistic opportunities.'
Phoenix publicly entered rehab in Spring 2005 for treatment of alcoholism. His publicist said: 'He was uncomfortable with the way that he was living his life and found the courage to deal with the disease.' Following his release from rehab, Phoenix admitted he started drinking more while he was filming his role as Johnny Cash in Walk The Line. He said: 'It was then that I became aware of my drinking. I wasn't an everyday drinker but didn't have anything else to do, anything to hold me down. I was leaning on alcohol to make me feel OK. That's what it really was.'
Phoenix's older brother River famously died of a drug overdose after collapsing outside the Viper Room nightclub on Sunset Boulevard in October 1993. River, who was just 23 when he died, was at the club with Joaquin, their sister Summer and the actress Samantha Mathis. The then-19-year-old Joaquin made an emergency 911 call in a bid to save River, who later died in hospital.