Last week we heard that Josh Hartnett was among a short list of actors who Marvel wanted to play Loki, and that Alexander Skarsgård (True Blood) was in the running to play the thunder God himself, Thor. Well now a source tells Deadline Hollywood that Hartnett is actually in the running for Thor, not Loki, and that Natalie Portman is apparently front runner to play the female lead.

Sure, there’s a big push to cast Josh Hartnett in the winged helmet, which is ironic since Warner Bros once upon a time threw an amazing amount of money at him to play Superman but he refused. But my sources say there’s an equally powerful lobby to cast an unknown. I’ve heard that, besides Hartnett, the following actors are being tested: Charlie Hunnam (the British co-star of the F/X series Sons Of Anarchy); Tom Hiddleston (award-winning British actor and RADA graduate who played Winston Churchill’s son in HBO’s The Gathering Storm), Alexandar Skarsgard (Stellan’s son who has appeared in the HBO Iraq War miniseries Generation Kill and vampire drama True Blood, and who’s definitely visually right for the role), and Joel Kinnaman (some Danish dude). Meanwhile, I’m told Natalie Portman is in the lead for the female lead.

Out of all of Marvel’s upcoming movies Thor will be one that will be the trickiest to convert onto the big screen (apart from whoever gets the job of joining the characters together for The Avengers). With the release date being pushed back to 2011 it gives director Kenneth Branagh more time to sort everything out, including who he will cast as the lead. I haven’t read a Thor comic so I have no idea who Natalie Portman would play if this turns out to be true, although I like her as an actress.