"I look like my younger brother," Allen said. "It's just depressing."
ET was also on hand for Home Improvement's first taping in 1991, when Jonathan Taylor Thomas was 10, Zachery Ty Bryan was nine and Taran Noah Smith was just seven years old.
"It was so much fun on the set," Richardson recalled of their days on the show. "We would just crack up and just lose it and not be able to get it together."
Allen said he actually still sees Smith, who works with his oldest daughter, Katherine, on the production side of the entertainment business. Allen also plays golf with Richard Karn, who played Allen's right-hand man, Al Borland.