Smart Guy was about a gifted youngster called TJ Henderson, who was transferred into High School at the age of 10 because of how intelligent he was. TJ was played by actor Tahj Mowry, who is now 26 years old!
Here's a picture of what TJ (Tahj Mowry) looks like now:
Remember Mo, who was Marcus Henderson's best friend?
Remember Yvette, TJ's older sister, who Mo was always hitting on? (Played by Essence Atkins).
Remember the intro song, which basically repeated the sentence "He's a smart guy!"
Here's an episode: