Nicole Kidman helps Naomi Watts out of a tight spot Nicole Kidman and Naomi Watts / Pic: Graylock.com Source: News Limited THEIR relationship might bounce from best friends to frenemies on occasion, but Nicole Kidman and Naomi Watts have proven they can still help a sister out when the time calls for it. Kidman is stepping in to fill a role in Werner Herzog's new movie Queen Of The Desert after Watts had to pull out due to a schedule conflict. The Oscar winning actress will play the part of 20th Century explorer Gertrude Bell. It's no wonder the real-life BFFs were both attracted to the plum role of Bell: writer, archaeologist and attache for the British Empire, who is credited with helping to catalyse the formation of the Middle East at the dawn of the 20th century. After meeting as teenagers on Aussie film Flirting in 1991, Kidman and Watts have long walked the fine line between close friends and professional rivals. On the media circuit ahead of her first Oscar nomination a role in The Impossible last year, Watts praised Kidman for keeping her stay positive when she tried to break into Hollywood. "There were moments when I was sure I was done ... but I didn't have a plan B really, I didn't," she told CBS's Lee Cowan. Nicole Kidman and Naomi Watts / Pic: AFP Source: AFP [Nicole] She kept saying, 'It's just going to take one thing, one thing, Nay, and you know, if you're in a hit film ... then everything changes.' However, Kidman reportedly snubbed a request from the producers of 60 Minutes to film a segment discussing Watts' role in the film - which could have given her a pre-Oscars push. Both actresses play famous royals this year, Watts as Princess Diana in the biopic Diana and Kidman as Grace Kelly in Grace Of Monaco. They were also both considered to be early favourites for a best actress Academy Award nomination, but Diana has received extremely negative reviews after premiering in the UK. The Daily Mail's David Edwards wrote that "Wesley Snipes in a blonde wig would be more convincing" than Watts performance.