I have heard that the only way to get an authentic dedication from David Tennant is from writing to him via venue. does anyone have that address?

Oh I see thank you, so the IRC can be substituted for english stamps?

I've been reading the stickys but i still have a few questions. Where do I get these IRCs? I'm in the US wanting to write to people in the UK. I'm kind of confused about the whole process....if there's anyone from the US willing to give me a general overview of the steps you take? Thanks.