Congratulations & hope you'll be very happy. I assume the house is mortgaged. To get the house in joint names you need to sign a deed of transfer into your joint names. Your lender will need to consent and to join into the deed. If you do this when you are married and it is your family home, there is no stamp duty, land registry fees or CAT. However there will be a small legal fee to pay to the solicitor. Naturally the owner of the house will need to get independant legal advice before transferring. There may be an issue as regards the initial equity in the house ( assuming you contribute equally to the mortgage in the future, but if not, then this will also be an issue), but it is a matter entirely for your selves to decide having obtained the relevant legal advice.