"He's a chubby little guy, so he keeps seeing Mommy's belly, and then he looks at his own belly and says, 'I have a baby too,'" Scott told People at the premiere, revealing that Keller is almost five months pregnant with another baby boy. "He's going to be a great big brother. If he doesn't kill his little brother within the first six weeks, then we're going to be great."
Home Again hits theaters on Sept. 8.
See more on Scott in the video below.
Additional reporting by Brendon Geoffrion.