Marvel's The Avengers: Age of Ultron has added another member to its ensemble cast - actress Kim Soo-hyun, a.k.a. Claudia Kim, is joining the film. Rumors about the actress' appearance in sequel started swirling as early as January, and Comic Book Movie reports she and her Disney Korea rep have officially made the announcement. But who is relatively unknown actress playing? She's not talking.

Soo-hyun posted about the announcement on Twitter this week (along with the above picture) and said: "After a long wait, I’m happy to be back with great news. I have a lot to do ahead of me, but for now, the words ‘Welcome to the Marvel Universe’ are amazing and kind of overwhelming. I was a fan of Marvel Comics, and if you really like something, looks like fate can make it happen.”Korean site Osen stated they spoke with Soo-hyun's rep about the role, and he told them, “It would be a spoiler, so we can’t tell you which character she will play." The earlier rumors were all over the place stating she was a villain or a doctor treating Tony Stark. We'll have to wait and see.This announcement comes ahead of the Los Angeles premiere of Captain America: The Winter Solider which Kim Soo-hyun will be attending before she starts filming the Avengers sequel in South Korea next month.

Amy Ratcliffe is a writer for IGN TV. You can follow her on on Twitter at @Amy_Geek and IGN at alratcliffe