Neither Andy Lau nor Joshua Dallas will be appearing in Iron Man 3 and Thor 2, respectively.
Lau was to play a still unnamed scientist friend of Stark’s who aids the Iron Avenger in his dealings in China. Lau ended up turning down the production to focus on time with his family, particularly his newborn daughter. Can’t fault a guy for that! A replacement is already being sought, with Chen Daoming (Hero) and Wu Xiubo (Before The Dawn) topping the list.
Moving on, Dallas will be unable to reprise his role as Fandral in the Thor sequel due to his commitment to ABC’s Once Upon A Time. In an ironic twist of fate, it appears that his replacement will be none other than Zachary Levi. For those who don’t remember, Levi was originally cast as Fandral in the first film, but had to bow out when Chuck ended up being renewed for another season.
Source | Latino Review