Use the other address. i did and i got a personalised autograph

Hey,,
Congrats on ur succses,
Do u know if i have to put a uk stamp or an american stamp on the envolope??
Thanks
x x {love}

Hey,, Congrats on your succses,
Just a quick question do u know if i just need to put a uk stamp on or have to get an american stamp ??
Thanks {love}