Why It Could Work: With thick headed brow and square jaw, Damon can pull off the look of Sinatra very well, give or take a few adjustments. He dives into his roles with method intensity, and has also worked with Scorsese previously, in The Departed.

How It Could Fail: Anyone who has heard Damon sing “Afternoon Delight” in Good Will Hunting, knows that he cannot carry a tune, a major factor if Scorsese chose to have his actors sing. Also, a clean cut Boston boy portraying one of the most prominent of all Italian Americans? Maybe not.

Why It Could Work: Mark Ruffalo’s full rounded face would be an advantage when portraying the legendary crooner in his later stages. Plus, as an Italian American, he has an ethnic advantage, and has just completed work on Martin Scorsese's upcoming thriller, Shutter Island.

How It Could Fail: Ruffalo has never show any musical ability, with the majority of his filmography leaning towards more darker territory.

Why It Could Work: Spacey is an all rounder: a song and dance man, whose acting prowess has garnered him 2 Oscar wins. Yet more important is his ability to put on the old school charm, as seen in L.A. Confidential and Beyond the Sea, where he portrayed crooner Bobby Darin.

How It Could Fail: As mentioned, Spacey did play Bobby Darin, so Sinatra could be one crooner too many. Another issue is that of age: at 50, Spacey is pushing it, if Scorsese intends the one actor to portray Sinatra from young man to elder statesman.

Why It Could Work: Comeback kid Robert Downey Jnr. can handle vocal duties, having released critically acclaimed album, The Futursit, in 2004. He is a talented and charming actor, and has a knack for tackling difficult roles seemingly out of his league  – Chaplin, Tropic Thunder – which has garnered him applause as one of his generations most talented actors.

How It Could Fail: Yeah, he’s charming. But in a quirky, witty sort of way, not something that would mesh well with Sinatra’s old school pizzazz. Looks wise, too, he just does not match Sinatra’s distinct features, with the addition of too much make up effects a distraction.

Why It Could Work: Give Emile Hirsch the right suit and hairstyle, and he can pull off a convincing young Sinatra, easily. One of Hollywood’s best young talents, Hirsch would take on a challenge like his and gobble it down with glee.

How It Could Fail: Portraying a much older Sinatra will be a stretch, even for an actor as talented as Hirsch.  

Why It Could Work: Harry Connick Jr. was deemed Sinatra’s successor at the start of his singing career, so he can pull off Sinatra’s tunes, no sweat. Add to the mix that he can act, and can pass off as a middle age Sinatra in the looks department.

How It Could Fail: Headlining a film of this magnitude could be out of his depth. Also, he is far too gone to play the younger Sinatra.

Why It Could Work: Perhaps one of the most versatile and talented actors of his –or any other – generation, Depp would bring an air of credibility to Sinatra’s story. Also, his ability to bring on the goombah charm –as evident in the underrated Donnie Brasco – is a bonus.

How It Could Fail: Yeah, Depp can act and even carry a tune. But his musical taste and quirly screen charm screams more rocker than crooner. Really, he should be portraying Iggy Pop or David Bowie, not Frank Sinatra.

Why It Could Work: James Franco has had experience portraying legends, having won critical acclaim with James Dean. Last year saw the burgeoning thespian show off his acting chops even further, with two varied performances in Pineapple Express and Milk. And, his boyish looks helps when portraying Sinatra in his early years, and he just might be able to pull off a middle-aged Frank as well.

How It Could Fail: There is no indication whether Franco has any musical ability. Also, his looks could become a distraction, proving to be too sexy to be the Chairman of the Board.

Why It Could Work: With four collaborations in the books (including the upcoming Shutter Island), Scorsese has complete trust in Leonardo Di Caprio, and for good reason: he is perhaps the greatest actor working today, with his thespian talent matched with a smooth charm, acute maturity, and still youthful looks, which will work in his favour when portraying Sinatra during varied stages of his storied life.

How It Could Fail: It is doubtful that Di Caprio can carry a tune, even though he has attempted to redeem that fact by hiring a top class vocal coach to help shape of for the part.

Why It Could Work: The criminally underrated James Marsden is perfect fit for Sinatra: he can act, is credible in terms of look (including the needed blue eyes), and can sing a dream. With several acclaimed supporting turn under his belt, Sinatra should be his ticket to leading man territory.

How It Could Fail: Unfortunately, star power – or the lack of – is Marsden’s only weakness, with not enough wattage to headline a production as big as this. Hopefully logic will prevail, and Marsden can prove himself to be the most credible choice.