▲One of the greatest living actors has also mastered her rendition of British characters, as seen by her Oscar win for playing Margaret Thatcher in 'The Iron Lady' (2011). Variety gives her accent a 4.9 out of 5.

▲Hathaway's portrayal of Jane Austen in 'Becoming Jane' (2007) received mixed reviews from critics, but The Los Angeles Times says she "sounded like a high school acting student attempting a British accent," and gave her accent a 2.5 out of 4.

▲Graham plays a feisty prostitute in 'From Hell' (2001), alongside Johnny Depp in his rendition of Jack the Ripper. WhatCulture describes Graham's attempt at an East London Cockney accent as "something so sinister, so off-putting." Harsh.

▲Jolie's accent in 'Lara Croft: Tomb Raider' (2000) has been described as decent, but unconvincing.

▲Zellweger is perfect as Bridget Jones in 'Bridget Jones' Diary.' If her accent sounds exaggerated, it's probably intentional, as the British characters' in the film also exaggerate theirs. Vanity gives her accent a solid 4.5 out of 5.

▲The actor had already successfully played a Brit in 'Chaplin' (1992), and his rendition of everyone's favorite detective didn't disappoint either, according to BBC America.

▲Astin has to put on a bit of an accent to play Samwise in 'Lord of the Rings,' but how does he fare? IMDb says he does a West Country accent well, "but there were times you could tell."

▲Portman plays Evey in 'V for Vendetta' (2005), a young working-class woman caught up in V's mission. Her accents received some mixed reviews. Vanity gives it a 3.5 out 5. But she may have worked on it, as The Los Angeles Times praises her accent later in 'The Other Boleyn Girl,' giving it a 3.5 out of 4.

▲Depp's accent in 'Pirates of the Caribbean' confused a lot of people, but his hammed up British accent appeared to have been intentional to heighten the strangeness of Captain Jack Sparrow, according to IMDb.

▲All right, this one actually might be the worst rendition of a British accent in modern American history. Even he has said so. Vanity gives it a 1.6 out of 5.

▲McDormand proved to be great at accents in 'Fargo' (1996), when she fooled everyone with her Minnesota inflection. And she did it again as the British Miss Pettigrew in 'Miss Pettigrew Lives for a Day' (2008). The Los Angeles Times gives her accent a 4 out of 5.

▲The American actor was married to British rock star Chris Martin from Coldplay for more than a decade, but her British enunciation was spot on even before then. Her role in 'Shakespeare in Love' earned her an Oscar, and The Los Angeles Times gives her British accent a 4 out of 4.

▲Lohan was adorable as the twins Hallie Parker and Annie James in 'The Parent Trap' (1998), the latter of which was raised in the UK. Regarding her accent, The Telegraph wrote that the then-11-year-old "sounded like she'd swallowed a whole crate of" plums.

▲Brando's indescribable accent in 'Mutiny on the Bounty' (1962) "nearly sinks the seafaring epic," as The Los Angeles Times put it.

▲Madonna's accent in 'Swept Away' (2002) "is bad, annoying, and it grates," according to WhatCulture.

▲Malkovich plays a Brit in the TV series 'Crossbones,' and IMDb says he uses "a pretty stagey British accent that I doubt the historical Blackbeard whom he portrays would have used, but he maintains it consistently."

▲IMDb contends that British viewers were stunned to learn Whitaker is American after seeing him play a British soldier in 'The Crying Game' (1992).

▲The Los Angeles Times praises Witherspoon's "posh" British accent in 'Vanity Fair' (2004), comparing her to Meryl Streep.

▲The actor has received high praise for his accent as a British vampire in 'Buffy the Vampire Slayer.' Denisof actually lived and went to school in the UK, so that probably explains it.

▲Anderson plays British roles in 'Bleak House' (2005), as well as in the TV series 'The Fall'—and her accent is flawless. But this may be a bit unfair to the other contenders as Anderson lived the first decade of her life in London.

▲Roberts played the Evil Queen in 'Mirror Mirror' (2012) but sadly for her, "the strongest thing you'll take away from the performance is her bad English/medieval accent," Alloy wrote.

▲The Los Angeles Times praised Johansson's King English in 'The Other Boleyn Girl,' and gives it a 3.5 out of 4. Johansson also played a Brit in 'The Prestige' (2006).

▲The 'Agent Carter' actor plays characters of various nationalities in the TV series 'Dollhouse,' including a Brit. IMDb calls his attempt "serviceable."

▲LaBeouf's appearance in Lars Von Trier's arthouse film 'Nymphomaniac' is short—but it was enough to be considered bad. As ShortList put it, "All that time denying his fame and wearing a bag over his head didn't allow poor Shia LaBeouf much time to concentrate on his London accent."

▲If you keep forgetting that Dinklage is a New Jerseyan through-and-through, you're not alone. His portrayal of the youngest Lannister sibling in 'Game of Thrones' is so incredible, it's hard to remember he isn't actually Tyrion Lannister. As far as his accent goes, Business Insider classifies Dinklage's attempt at an English accent as having "varying degrees of success."

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Mortensen famously played Aragorn in 'Lord of the Rings' with a British accent that is a "bit mumbly in places but excellent," according to IMDb.

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Costner in 'Robin Hood: Prince of Thieves' (1991) may be the worst rendition of a British accent in American history. The Los Angeles Times says "his feeble attempt at an accent is an embarrassment," and gives it a 1 out of 4.

▲Gyllenhaal has starred in a few British productions, including 'Nanny McPhee and the Big Bang' (2010) and the TV miniseries 'The Honourable Woman.' IMDb praises her accent: 'A very solid attempt, well done!'

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IMDb says Tudyk "does a very good middle-of-the-road English accent" in 'Death at Funeral' (2007).

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Casting an actor to portray a different nationality is always tricky. The feat becomes even more complicated when the actors are tasked with portraying prominent historical characters in their respective culture. A great example is 'The Other Boleyn Girl,' which received harsh criticism for casting two American women to play the Boleyn sisters, Anne (Natalie Portman) and Mary (Scarlett Johansson). Here are some Americans who have played British characters, as well as what critics have to say about their British accents.Do you agree with the critics?