Hi! Yes she does reply to fan mail! She had recently been on tour, one of which locations was where I live, Singapore. Here's the link to a previous success. It appears that she does include her own photos and will also sign yours.
http://www.fanmail.biz/mboard/viewtopic.php?t=226664
Best of luck!

Hi there.

I currently live in Jersey in the Channel Islands and I am a huge fan of Jessie J. I have currently written her a letter which is very close to the heart and quite personal. It consists of about 7 or 8 pages. I have requested a letter back with a signed photo and also included a SAE.

Does anybody know if she replies to fan mail and if I will receive a letter and signed photo back?

I also enclosed a couple of gifts for her, a necklace and a bracelet.

Do I have to supply a photo, or will she automatically send one?

If anybody has any other information they know, please do let me know.

As I Jessie J!