Some actors have the wonderful skill of changing themselves, chameleon-like, to fit into any role they turn their hands to, including putting on an accent that even locals would think was authentic.
Hugh Laurie, Idris Elba, Emma Watson and Andrew Garfield are amongst the Brits who have crossed the pond and nailed the stateside accent.
The 11 actors on this list, however, didn't managed to convince us they were anything but a Brit awkwardly putting on an American accent.
Ray Winstone - The Departed
The dense, multi-layered crime thriller The Departed was widely-praised for its characters' authentic Boston accents and won four Oscars, including Best Picture and Best Director Martin Scorsese.
One accent doesn't quite fit, that is the one of 'The Daddy' Ray Winstone.
While Ray's American accent isn't as terrible as some of those on this list, it's the typical generic accent that makes it stand out amongst the accents from the likes of Matt Damon and Mark Wahlberg.
Terrible accent rating: 2/5 - it wasn't a bad accent; it just didn't fit with rest of the film's authenticity.
Rebecca Hall - The Town
British actress Rebecca Hall featured in the star-studded 2010 crime thriller The Town alongside Ben Affleck, Blake Lively, Jon Hamm and Jeremy Renner.
Hall, who went on to feature in Iron Man 3 and Transcendence, plays bank manager Claire Keesey who is taken hostage and released by bank robbers.
Supposedly from Boston, Hall gives it her all with a generic American accent, which manages to hold strong, except for a few lines scattered throughout the film which are just her full-on English accent.
Terrible accent rating: 1/5 - apart from the odd line dropping into her native accent, it was a pretty decent effort.
Charlie Hunnam - Pacific Rim
Newcastle-born Hunnam already has a pretty unusual Transatlantic accent as it is (displayed in this interview on Conan), but he managed a passable American accent (albeit mostly gruff grunts) while playing Jax on Sons of Anarchy.
But it would seem that he took a trip back to 'jolly old England' before filming Guillermo Del Toro's giant robot action movie, as he reverted back to his unusual, 'not quite English' accent.
Terrible accent rating: 4/5 - he's can do a better accent than that, and he knows it.
Dominic Cooper - Captain America: The First Avenger
London-born Dominic Cooper must have been overjoyed when he landed the role of Tony Stark's father Howard in the first Captain America film.
Playing New York native scientist, Cooper's accent didn't hit the mark and it was pointed out as one of the few failings in a brilliant Captain America flick.
Terrible accent rating: 3/5 - it's not the best American accent from a British star, but it got more hate than it deserved.
Claire Forlani - Mallrats
Up there with Clerks as one of Kevin Smith's finest films, Mallrats is set in a mall (hence the title) in New Jersey and features Twickenham-born Claire Forlani as Brandi.
With her character hailing from New Jersey, Forlani put on an accent that sounds that wouldn't sound out of place in Downton Abbey.
Claire, who also played characters in The Rock and Meet Joe Black, is still featuring in American dramas, most notably on the small screen in NCIS and CSI: NY.
Terrible accent rating: 5/5 - was she even trying? It'd probably be less acceptable if she was.
Clive Owen - Inside Man
Clive Owen played bank robber Dalton Russell in the 2006 crime thriller Inside Man alongside Denzel Washington.
Set in Manhattan, it would appear that Owen is attempting a New York accent, although a lot of his lines sound like he's just saying them in his normal English accent.
Terrible accent rating: 3/5 - it's hard to tell if he's actually bothering to do an accent in places.
Michael Caine - On Deadly Ground
Probably Michael Caine's most famous trait is his cockney accent, and in most of his film roles he's been able to speak in his native accent.
Possibly because when he has put on an accent, it's come out like it did in the Steven Seagal action flick On Deadly Ground.
Caine plays ruthless, corrupt and generally unpleasant CEO Michael Jennings who has unnervingly black hair.
Maybe as of how well we know Michael Caine's natural London accent that his accent sounds so jarring, or perhaps it's just that he is unable to do a convincing American accent - it's definitely that.
Terrible accent rating: 4/5 - an actor the calibre of Michael Caine should put in a better accent performance than that.
Liam Neeson - Darkman
A few people questioned why in Taken, Liam Neeson played retired CIA operative Bryan Mills with a heavy Northern Irish accent.
Neeson also told Seth MacFarlane that he would only star in the Family Guy writer's western comedy A Million Ways to Die in the West if he could use his native accent, after MacFarlane had mocked his accent in a Family Guy episode.
Perhaps it worked out for the best, after his role in superhero film Darkman, where he plays scientist Dr. Peyton Westlake who becomes Darkman with an atrocious Liam Neeson/Brooklyn hybrid accent.
Terrible accent rating: 4/5 - a valiant attempt, but it was never going to work, stick to violently assaulting henchmen Liam.
Colin Firth - Main Street
After Renée Zellweger was praised for her English accent in Bridget Jones' Diary, Colin Firth thought that it would work the other way when he appeared as Texan Gus Leroy in 2010's Main Street.
Unfortunately Colin's attempts at an "how y'all doin'" Texan accent weren't as successful as his Bridget Jones co-star as his accent was a generic 'Deep South' accent, that he maintained only some of the time.
Terrible accent rating: 3/5 - kudos for attempting a regional accent, didn't work so well when he tried to actually speak it.
Jason Statham - The One
Jason Statham appears as an ass-kicking Englishman in the Crank and Expendables films no matter where the movie his set.
Perhaps that's because 'The Stathe' put on his best American accent in the Jet Li film The One back in 2001 and Hollywood decided that he should probably stick to the martial arts and leave accents alone.
Terrible accent rating: 4/5 - it's virtually the same as his normal English accent, but a bit 'not right'.
Gerard Butler – The Bounty Hunter
After an atrocious Irish impression in P.S. I Love You, Scotsman Gerard Butler put on his best American accent while starring opposite Jennifer Aniston in romcom The Bounty Hunter.
As a former NYPD detective, Gerard layered the 'New Yoyk' accent on extremely thickly, which was fighting a war in his mouth with the broad Scottish accent.