Hulu’s Only Murders in the Building has locked in the first major cast addition for the upcoming fifth season. Keegan-Michael Key has signed on for a recurring role. Details about the storylines and new characters are being kept under wraps. Production on the new season, which will be solving Lester’s murder, started earlier this week in New York with the show’s four series regulars — Steve Martin, Martin Short and Selena Gomez as well as Michael Cyril Creighton — returning. Once again, they will be surrounded by a recurring cast of big names, starting with Key.