The proud mom, wearing a bright canary yellow Monique Lhuillier frock, told Us that Jack has been "giggling" and is really "starting to know things."
"He does funny things like [mock pouting]," Faris said, making faces to demonstrate her little man's silly behavior. One day earlier, the Emmy presenter told Us that Jack has even begun to say "Mama."
"He said 'Mama' the other day. I have no idea if he meant it about me," the Mom actress said with a laugh. "But he was looking at me. And now I'm one of those corny people that's like (in country accent), 'My child just grew a tooth!'"
Faris, 36, and husband Chris Pratt, 34, welcomed their bundle of joy in August 2012, and having a little one at home to look after has since convinced the actress to move from the big screen to TV, she told reporters at the TCA panel for Mom in July.
"I have a son. So I was sort of thinking, 'You know, maybe I'll just let my husband work, and I'll just laze around, sit by the pool,'" she said at the time. "Different priorities."