Short answer: probably.
Your legal status changes upon marriage and any existing will is automatically cancelled (or “revoked”) unless it specifically states otherwise. Most wills do not state otherwise, so you should be ready to make a new one as soon as possible after marrying or entering a civil partnership.
The months before your wedding can be hectic, with so much planning for the big day, but making a will should be on your list of “things to do” shortly after the event. If your existing will is revoked and you do not create a new one, your estate will be divided according to the government’s intestacy rules in the event of your death, and not according to your wishes.
It is important to update your will or create a new will whenever your circumstances change, for example getting married or entering a civil partnership, getting divorced or dissolving a civil partnership, or when you have children.