The Toronto-born McDermott was accompanied by wife Tori Spelling to the swearing-in ceremony in Los Angeles. Dean was one of 3,000 new citizens who pledged their allegiance to the United States.
“I am so proud and overwhelmed all at the same time,” the reality TV star told Us.
“He’s wanted this for a long time,” added his proud wife.
The Home Sweet Hollywood stars have been married four years and have two kids.
The couple celebrated Dean’s new status with lunch from Taco Bell.