sociated PressDecember 12, 2012Actors Cate Blanchett and Ian McKellan arrive at the UK premiere of The Hobbit: An Unexpected Journey at The Odeon Leicester Square, London on Wednesday, Dec. 12, 2012. (Photo by Jon Furniss/Invision/AP)LONDON (AP) ??? Prince William is joining stars such as Ian McKellen and Cate Blanchett on the red carpet in London for the U.K. premiere of The Hobbit, the first