The feel-good sitcom Family Matters premiered in 1989, and is perhaps best remembered for the family patriarch Carl Winslow’s (Reginald VelJohnson) feud with his nerdy neighbor Steve Urkel (Jaleel White).

White was 12 when the show began, but 21 when it ended. Between the ages of 12 and 21, people do some serious changing. Jaleel White, the actor who played Steve Urkel on Family Matters, was no different.

The reason behind the costume change was because executives found Urkel’s physical transformation into adulthood too distracting. White elaborates on his, erm, growth spurt in his new memoir Growing Up Urkel and disclosed how he was told by producers the plans to keep Urkel evolving but also family-friendly.