Harry potter and the deathly hallows premiere ?

Hei guys, does everyone somthing about the Harry Potter 7 -part 1 world premiere in Londra ? i think it's in leicester square, right ?But when ??? I just want to see helena bonham carter and the other actors, not the movie ( because my english is not the best, i should watch it in german ;) ) .. do i have to pay thaan?