Cameron Crowe has defended casting Emma Stone in 'Aloha'.

The 57-year-old director came under fire when it was revealed the 'Birdman' star was to play Hawaiian Captain Allison NG in the comedy drama as many deemed the flame-haired beauty's look unsuitable for the role.

However, Crowe has spoken out against his critics and insisted Emma, 26, was perfect for the part as the woman on which the character was based was a redhead herself.

He wrote on his blog The Uncool: ''I have heard your words and your disappointment, and I offer you a heart-felt apology to all who felt this was an odd or misguided casting choice. As far back as 2007, Captain Allison Ng was written to be a super-proud quarter Hawaiian who was frustrated that, by all outward appearances, she looked nothing like one.

''A half-Chinese father was meant to show the surprising mix of cultures often prevalent in Hawaii. Extremely proud of her unlikely heritage, she feels personally compelled to over-explain every chance she gets. The character was based on a real-life, red-headed local who did just that.''

Although many Hawaiian locals were cast in other roles in the film, Crowe goes on to apologise for any offence he caused by choosing Arizona-born Emma for the part.

He added: ''If any part of her fine characterisation has caused consternation and controversy, I am the one to blame.''