FAN MAIL ADDRESSES:

Henry Cavill
United Agents Ltd.
12-26 Lexington Street
London, W1F 0LE
UK

or

Henry Cavill
c/o CAA
2000 Avenue of the Stars
Los Angeles
CA 90067
USA

How to send your fan mail and autograph requests to Henry Cavill?:

If you want to request an autograph, follow the guidelines bellow. If you just want to mail a letter with the address above, and do not want anything back, then you can stop reading! If you live in UK send a properly stamped and self addressed envelope (minimum size 8.5″ x 4″) with your request letter and a photo. You can include a piece of cardboard to keep the photo from bending in shipping and also add “Do Not Bend” on the envelopes. Send your letter and wait. On average, there is going to be a 3+ month wait for a response. If you do not live in UK, add several International Reply Coupons. The International Reply Coupons (IRC) will be used by the receiver to purchase english stamps. You can only get them at your post office. Place the IRCs into the envelope, not on it.

Source: Fanmail.biz