When Kelley was originally cast, the character of Walt was a 10-year-old boy, but, after two seasons, Kelley no longer looked 10. While the first four seasons move slowly through time and only months have passed on the show, the actual filming stretched over several years. The show's writers dealt with this by sending Michael and Walt away from the island at the end of the second season. In his brief appearance at the end of season three, Kelley is noticeably taller and older with a deeper voice. This fact is acknowledged by Locke in "Confirmed Dead". In the season four episode, "Meet Kevin Johnson", Kelley makes a brief uncredited cameo as Walt in the episode's flashbacks. Make-up and CGI were used to make Kelley look younger and more like a 10-year-old. In the season four finale, "There's No Place Like Home", Walt appears in a flash-forward, but this scene is set about three years after the plane crash, so Kelley's older appearance is not a problem. When asked about the production difficulties associated with Walt and possible appearances of the character in the fourth season, co-creator Damon Lindelof stated: "We've always known Malcolm was going to grow faster than we could shoot the show. And we planned for it. Trust us. Please trust us. You'll see again. But you're gonna have to be patient. Sorry."