HOUSTON, Texas (KHOU) -- The U.S. Postal Service has announced it will make deliveries on Sunday, Christmas Day.

"We're going to have our employees out. They'll be delivering express packages. So we're going to ensure that our customers receive their items on Christmas Day as well." said Nikki Johnson, a communications specialist with the U.S. Postal Service.

Those who haven't mailed out packages yet will have to pay for Express Delivery and the packages must be mailed by 5 p.m. Friday to guarantee a Christmas drop-off.

If you missed the service counter, just look for self-service kiosks as many Houston post offices have them.

"If you do not know your zip code, the beauty about that machine is, it will be able to look up that zip code for you." said Johnson.

The machine also calculates the cost of the postage.

Just be prepared to pay more than you would for a .47 cent stamp.

FILE PHOTO: A man uses a self service machine at a United States Post Office (USPS) on September 25, 2013 in New York City.