Hi, Karen!
Mickey's Very Merry Christmas Party sounds like the perfect way to start your magical Walt Disney World® Resort vacation - it's festive fun for the whole family.
Available on select nights, this separately-ticketed event officially begins at 7:00pm, but guests with a party ticket are usually granted entry into Magic Kingdom Park as early as 4:00pm. Should you head to the park to take advantage of "early entry" you will not need additional theme park admission, your party ticket will get you in.
At the main entrance to Magic Kingdom, be sure to look for the touch points marked for guests entering with a Mickey's Very Merry Christmas Party ticket (it's usually the entrances to your right when facing the train station). Cast Members will be on hand to greet you after scanning your MagicBand, or plastic card, to provide you with your official party wristband. All guests attending this yuletide event, must have a wristband.
I hope this answers your question, Karen! Please let me know if you should have any additional last-minute questions as you continue planning. Mickey's Very Merry Christmas Party is one of my favorite seasonal events, so I am here to help make it magical.
Faith