Cate Blanchett's sons think she's Queen Elizabeth I.The Australian actress - who wore a clingy, strapless, sequined Vivienne Westwood dress and jacket for the premiere of 'Elizabeth: The Golden Age' in London's Leicester Square last night - revealed her two boys, five-year-old Dashiell and three-year-old Roman, get confused by their mother's ever-changing film roles.Cate told BANG Showbiz: "It's really difficult for them to differentiate between fantasy and reality, but I think that hopefully they are starting to learn that now."The 38-year-old actress - who is married to playwright Andrew Upton - also admitted she found it intimidating reprising her role as the infamous British monarch, because she was following in the footsteps of actresses including Sarah Bernhardt and Dame Helen Mirren.Cate, who first played the historical character in 'Elizabeth', said: "There is a legacy of brilliant actresses who have played Elizabeth - Sarah Bernhardt, Bette Davis, Glenda Jackson, Helen Mirren to name just a few - so to be part of that legacy is just amazing."It's like the female screen version of Hamlet or something. You do have to rise up to the role - it was a complicated role and she was a very complicated woman, which is always a challenge."Other stars to attend the glitzy premiere included Rhys Ifans, Richard E. Grant, Heather Graham and Cate's co-star Geoffrey Rush.