From acclaimed director Antoine Fuqua and starring Academy Award nominated Jake Gyllenhaal comes a story of tragedy, loss and the painful road to redemption.
The new Southpaw trailer last month featured Jake Gyllenhaal showing off an extremely toned torso.
But according to his trainer, former professional boxer Terry Claybon, it took a huge amount of work to get the 34-year-old actor ripped for the shoot, including six months of training before filming even started.
He also worked out for an incredible six hours per day, including 2000 sit ups, 1000 each morning and the same at night.
Of course, Gyllenhaal had to work even harder to get in shape because he had just dropped approximately 30lbs to play freelance crime reporter Lou, who stumbles upon the dangerous underworld of Los Angeles in Nightcrawler.
He not only returned to his normal weight - but he then put on another 15 pounds of pure muscle to play the desperate fighter Billy Hope.
His trainer Claybon told Yahoo: "Gradually we built up, day-by-day, to 2,000. It takes time to do that", and revealed that his exercise regime included, "three hours of boxing in the morning and three hours of strengthening, conditioning, and cardio at night."
Speaking about his weight loss for Nightcrawler, Gyllenhaal told Us Weekly: "I knew that [Lou] was literally and figuratively hungry, [so I got into the] mode where I was always a bit hungry.
"It's not different than getting into character for anything. It's more about believing where you are and being present where you are. Who's to say what the process is? I have a strange one ... but I love what I do."
Jake Gyllenhaal stars in the movie Southpaw.
Claybon explained to Yahoo that Gyllenhaal put back on the weight he had lost before gaining an extra 15 pounds of muscle for Southpaw.
Health experts told the Daily Telegraph that Gyllenhaal likely went on a high-protein diet, that likely included protein powder. He likely had to consume 130 grams of protein - two and a half times the daily recommended intake.
Health experts also told the Telegraph that such drastic body changes could cause long-term damage to his body.
Jake Gyllenhaal stars in the movie Southpaw.
The huge swing in Gyllenhaal's physique recalls other drastic changes actors have made in their bodies. Among the most recent and most notable is Matthew McConaughey's turn from Magic Mike hunk to Dallas Buyers Club AIDS patient.
Meanwhile, in Southpaw, Gyllenhaal plays Billy Hope, a professional boxer who must rebuild his life after his wife is killed and his daughter is taken away from him.
The recent trailer opens with Gyllenhaal's understatement: "I expected a hard fight. I put my family through a lot."
It then cuts to him in the ring bloodied and bruised as he takes a relentless pounding from an opponent, while his wife, played by Rachel McAdams and Curtis '50 Cent' Jackson look on in horror, before Hope suddenly turns it around sends the other boxer to the canvass.
Jake Gyllenhaal and Rachel McAdams in a scene from the movie Southpaw.
The reason Gyllenhaal's character allowed himself to take the beating in the first place is then explained.
"The more you get hit the harder you fight, I get it," his wife says. "Only now you've taken way to many hits before you get off. You cant fight like that any more. Think about her."
She's talking about the couple's only daughter Leila, who is played by film newcomer Oona Laurence. The youngster is fresh from lauded performances on Broadway as Matilda in the stage adaptation of the Roald Dahl classic.
Curtis '50 Cent' Jackson in a scene from the movie Southpaw.
But the trailer also reveals there's a much more devastating blow in store for Hope, when his wife is accidentally shot dead by a bodyguard during an altercation with he has with another boxer who had been taunting him, which McAdam's character had told him to walk away from.
And things get worse for the embattled boxer as the child protection services take his daughter away from him after he falls into a dangerous cycle of self destruction following the death of the child's mother.
Rita Ora in a scene from the movie Southpaw.
The film also stars Rita Ora, who recently played Christian Grey's sister in Fifty Shades Of Grey, as well as Forest Whitaker and Naoime Harris, replacing Lupita Nyong'o who dropped out in August.
