"In the last few months I have discovered a new passion and new purpose to my life," Pratt tells PEOPLE. "With this in mind, I have decided to take a break from my obligations to MTV's The Hills and discontinue filming any more episodes for this current season."
Currently studying software engineering with a focus on encryption at USC, Pratt says he's headed to work for American Defense Enterprises in their cyber security division.
"Upon learning of President Obama's declaration that the 'cyber threat is one of the most serious economic and national security challenges we face as a nation,' I have decided to refocus my energy and devote my full resources to helping America face this and other unprecedented challenges," he says.
"My new mission is this: To do my part in maintaining the technological superiority of the U.S. military and prevent emerging technologies from threatening our nation's security.
"With that being said, I am saddened to take this break from filming MTV's The Hills. At this time, however I feel I would not be honoring my country or myself if I were to continue this endeavor when I have the opportunity and the ability to assist our nation against these prevalent threats."
Pratt's wife, Heidi Montag, will remain on the show. Last week she announced that Pratt would no longer be her manager, and instead she hired a Malibu-based psychic named Aiden Chase.