Actor Nick Offerman is joining the cast of Amazon and BBC?s supernatural drama Good Omens. In the six-part series, which is based on the novel by Neil Gaiman and Terry Pratchett, Offerman will play a U.S. Ambassador and father of a child who is mistakenly believed to be the Antichrist. The former 'Parks and Recreation' star is the latest high-profile actor to join the series, which will feature Michael Sheen as the angel Aziraphale and David Tennant as the demon Crowley. Principal photography began in London earlier this year and will continue until the summer for a 2019 launch.