Richard Karn and Tim Allen

When ABC decided it was time for Last Man Standing to stage something of a Home Improvement reunion for its January 11 episode, Tim Allen reached out to pal and former costar Richard Karn, who played Tool Time sidekick Al. In the storyline, Allen's Mike Baxter hires an architect and must choose between his longtime colleague, Bill (Karn), and an attractive woman. (Tool Time girl Debbe Dunning was considered for the role, but Allen ultimately deemed her casting too "stunty.") There will be a few nods to Home Improvement, Karn reveals, including "a wonderful moment where I tell Tim's character, 'Say hi to your wife and three boys,' and he says, 'Actually, it's three girls.'"

During Karn's week on set, he was surprised to see Home Improvement's Jonathan Taylor Thomas, an aspiring filmmaker, shadowing the show's director. While JTT has taken a break from acting, Allen hopes he'll guest star soon. But you won't see Patricia Richardson. "Richard and JTT fit," Allen says. "But it would be weird to bring the old wife in with the new wife."

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