Adam? why?

Gordon Thomson was originally brought back to reprise the role of Adam. At the time, however, he was starring in the NBC daytime drama series, Santa Barbara, as Mason Capwell. Thomson appeared for fittings for the reunion, but reportedly the Dynasty production team did not give enough notice to Santa Barbara, who said Thomson was unavailable because he had to shoot their series. As Thomson had already been fitted for Adam's wardrobe in the series, producers had to scramble to find an actor who not only somewhat resembled Thomson, but could also fit into his wardrobe without alteration. The best they could come up with in short notice was Robin Sachs.

FYI: Thomson later sued Aaron Spelling over not being able to participate in the reunion.