The two welcomed their son Jack back in August 2012, but when he was born premature, the first-time parents were concerned.
"He was born at three pounds," Faris told GQ for the Men of the Year Issue. "And we were told, 'Okay, you need to be prepared for raising a special-needs child.'"
Faris said that though it was a shock, they took it in stride and focused on being the best parents they could be to their son.
"And we felt like it was devastating, but it also felt like, you know, 'We can do this'."
Pratt added, "He's alive."
The couple added that now, Jack is doing well and only needs to wear glasses.
Pratt didn't lose his classic sense of humor when explaining preschool to the magazine.
"I don't know what the f--- they do. Basically you just go there to get a cold," he said.