I talked about this signing HERE, so I'll get straight to the point.

Harrods' Weibo posted more details about the event:

-> MUSE will be sold starting from 10:00 am, one hour before the beginning of the event

-> Only the album sold there will be signed

-> It's limited to only 200 people

-> Every CD sold there will specially come with a hand strap, and only people with that hand strap are allowed in.

Thanks a lot to "A" for the input and to Carrot for the -very fast- translation.