According to ExtMovie, who's supposedly a pretty credible source in South Korea, some filming for The Avengers: Age of Ultron will take place in the East Asian country. Thanks to a heads up via SuperheroMovieNews and a translation via Reddit, the report claims the Marvel production will shoot in the Gangnam Station area, Gangnam Road Cheongdam bridge, and Songdo in April to May.
Furthermore, the report not only names multiple Korean actresses who are said to be up for a villain role, but it also details the role South Korea will play in the highly-anticipated sequel. Check it out:
Extra info - Hollywood's Marvel Team rented 1000sq ft (?) of filming equipment. Setting - Using S.Korea's background as an "IT super power", the film will have "Ultron" be created by some tech company in Gangnam. Ultron wakes up and wreaks havoc in surrounding area. 5 South Korean actresses are under consideration for a villain role. They are Kim So Yeon, Kim Min-hee, Han Go-eun, Han Ye-seul, and Kim Min-jung. It's 30 minutes worth of footage that'll be used in the movie and there will be total of 15 shootings. First filming will be on April 3rd, 2014. A lot of staffs are being hired for this shoot and they're scrambling as much HD cameras that are in Korea as they can get their hands on and Korean film industry invested $billion into this shoot. Again, this is just a rumor that I translated from a Korean website. The website itself is credible as directors and actors visit that website frequently to advertise their films and such. - Reddit
The Avengers: Age of Ultron stars Robert Downey Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Cobie Smulders, Jeremy Renner, Aaron Taylor-Johnson, Elizabeth Olsen, with Samuel L. Jackson and James Spader. The anticipated film is set to release on May 1, 2015.