Matt Damon makes a sizable decision in the latest "Downsizing" trailer, and it's not just shaving off all of his hair.

Paramount Pictures has released its latest preview for the upcoming film, and it teases the story of Paul Safranek (Damon), a man who makes the big decision to become much smaller. As we see in the trailer, he lives in a world where there is the option to "downsize" -- to be irreversibly shrunken down to a new size. The procedure is advertised as a way to make your money go further and increase your quality of life.

In the trailer, we see Paul and his wife, Audrey (Kristen Wiig), decide to go for it; they both go so far as to be shaved down for the procedure. However, when Paul wakes up in his new body size, he finds that Audrey hasn't been able to go through with it, leaving him to adjust to an entirely new life.

Watch below.

The film also stars Christoph Waltz, Hong Chau, Jason Sudeikis, Udo Kier, Niel Patrick Harris, and Laura Dern.

"Downsizing" is slated to hit theaters on Dec. 22.