If ever there was a square peg trying to fit into the round hole of Hollywood it's Matthew McConaughey. He's clearly got what it takes to be a leading man, but over the years he has struggled to really fit in.

He's tried various genres with mixed results, as audiences have struggled with him as the romantic lead in rom-coms (How to Lose a Guy in 10 Days, Failure to Launch) and as the action hero (Sahara). It appears however, that his latest tack could finally be paying off for him: acting. Sir Laurence Olivier would be so proud.

Recently, McConaughey has put in some impressive performances, most notably for his scene stealing in The Wolf of Wall Street and the excellent Mud. Here though, he takes his acting up an extra notch.

It's the mid-eighties and electrician and rodeo cowboy Ron Woodroof (McConaughey) is enjoying a lifestyle of debauchery, indulging as he does on a diet of sex, drugs and alcohol. After a run in with a bad lot however, he finds himself a little worse for wear in hospital. Although his injuries are superficial, the doctors do some blood tests and the results aren't good. Ron has contracted the HIV virus. Not only that, they give him 30 days to live.

His first reaction is that it's a mistake; after all, he isn't gay. After doing a little research however, he realises that you don't have to be, and that his penchant for unprotected sex has been his undoing.

Although not a studious type, he begins to get his head around what the best drugs are for his dour predicament. Annoyingly, they aren't approved by the FDA, which means the only way of getting them is illegally. This doesn't stop him however. Ron also realises that if he's struggling to get hold of the right medication, others are too. With the help of Rayon (Jared Leto), a transgender HIV sufferer, the pair open the doors on a clinic that gives those with AIDS a chance to get hold of drugs that they just can't get by prescription.

Oh, don't worry, the bongos are in the back, I don't leave home without them.

The first thing that will strike you about this film is the alarming lengths McConaughey has gone to as far as weight loss is concerned. From the off, his scrawny, underweight physique is borderline distressing to watch. Like many before him though who have done the same (Christian Bale for The Machinist and Tom Hanks for both Philadelphia and Cast Away, who McConaughey apparently contacted for weight loss advice), the physical presence is soon secondary to the performance given within it.

McConaughey clearly gives it his all, and certainly hits his stride as a confident performer. It's worthy of the Oscar nomination received for it, it's just a pity for him that it happens to be one of the most competitive years in recent years across all categories, but particularly this year, up against as he is, the likes of Leonardo DiCaprio (The Wolf of Wall Street), Christian Bale (American Hustle), Chiwetel Ejiofor (12 Years a Slave) and Bruce Dern (Nebraska). He may not win, but it certainly won't do his growing reputation as a serious acting force any harm.

Someone else who manages to impress is actor-cum-singer-cum-actor Jared Leto. Leto, who also fronts band 30 Seconds to Mars, hasn't acted in over four years, and yet still manages to give a career best performance as the transgender Rayon. He too is nominated for an Oscar (Best Supporting Actor) and has a better chance of winning than McConaughey does. Well deserved too, if he manages it.

Director Jean-Marc Vallée (The Young Victoria) does well drawing out remarkable performances from his two leading men, but their star turns do paper over the cracks of a fairly average script: although it is based on a remarkable true story, the script suffers from a lack of direction all round.

That shouldn't take away from McConaughey's achievements though. It's yet another statement of intent for the often derided actor (of course he hasn't helped himself much in the past with his naked bongo playing antics), that he's more than ready to be taken seriously in this new phase of his career. With his remarkable turn in the current US crime drama True Detective and Christopher Nolan's upcoming Interstellar, it doesn't look like letting up any time soon.