I really like the idea of Emily Blunt and think she could pull it off. Idina Menzel would be a better choice in my opinion, as long as she can fake a good accent. I guess she just has this thing about witches and the color green... But LotGK definitely cannot be played by Tilda Swinton. Don't make April Fools jokes about it or it'll come true!

LotGK definitely cannot be played by Tilda Swinton. Don't make April Fools jokes about it or it'll come true!

Well said Lilygloves!
I do like Idina Menzel and she's a really good actress, but I never saw her as LoTGK

Katie McGrath or Emily Blunt would both be great, they both have what I think LotGK should have looks wise...

Okay, the more I watch Merlin on Hulu and Netflix, the more I'm convinced that Katie McGrath should get the part.
Thanks, Jill, for saying welcome.

I think Olivia Wilde would be a good choice:
http://www.imdb.com/name/nm1312575/

This is actually a suggestion of somebody else, but how about Miranda Richardson as The Lady of the Green Kirtle?

Now she has acting experience, but I've never seen her act before. She played Rita Skeeter in Harry Potter, and played some role in Merlin's Apprentice, a TV mini series. However, when I saw her picture, she looks a lot like the LotGK I picture when I read.

http://www.imdb.com/name/nm0001669/

I haveno idea who should play her
but I noticed on here arguements about hair, I don't really care what her hair looks like as long as she is a good actress. but, wouldn't it be funny if she had green hair??

Actually, I always did imagine her in green with black hair to match the darkness of the underworld where she dwells most the time.. but then again, if she's pale faced, then dark hair would make her look vampire-ish.. Maybe a light brown or very dark blonde would work. And I agree with the whole "not making her overly seductive" addition, she did use magic to win Prince Rillian's heart after all, not her seductiveness, even though she was beautiful..

But as for who to play her?, I'm stumped on that, too. There's a lot of good actresses.. but I remember when the LWW crew hired Tilda to play Jadis and people were disappointed cause she wasn't that young looking.. Maybe the movie crew with pick someone perfect for LoGK, then again, maybe they won't.. if we ever get to that point when the movie is actually being made.. :S