Sigourney Weaver will transform in `Avatar` sequels

London: Actress Sigourney Weaver has revealed that she will "transform" in the forthcoming sequels of `Avatar`. The 64-year-old actress said that her role in the James Cameron-directed sequels will be challenging, reported Digital Spy."It will be challenging for me. I can`t talk about it, but my part is a little different in each one. I`ll transform somewhat," Weaver said. Weaver`s character Dr Grace Augustine was seemingly killed in the 2009 film, but will apparently return in some form in the sequels. Sam Worthington and Zoe Saldana will also return for the `Avatar` sequels, which will start filming in 2015.