The annual benefit, which raised over $1.5 million for City Year, an organization that helps keep students in school, was the first red carpet for the 5-year-old.
As they arrived, the actress sweetly bent down and asked him if he was comfortable with posing for photos, which he gamely did like a pro.
Once inside the Sony Studios in Culver City, Calif., Driver, 44, and Henry – along with Benjamin Stockham, who plays her son on the show About A Boy – had a blast checking on the interactive booths, games and food.
"He is having the time of his life," Driver told PEOPLE. In fact, the two were having so much fun Driver decided to bend the rules a bit.
"It's way past his bedtime. He is definitely going to fall asleep on the car ride home," she said. "But he's having such a good time!"