What’s on TV

SATURDAY NIGHT LIVE 11:29 p.m. on NBC. It’s hard to believe that Will Ferrell, who was an “S.N.L.” cast member for seven years and is credited with some of the show’s most memorable characters, will just now be hosting the show for a fifth time. On Saturday, Ferrell will be inaugurated into the so-called Five-Timers Club, joining a group of stars that includes Bill Murray, Justin Timberlake and Tina Fey. Before becoming a major movie star, Ferrell got big laughs as the cowbell-happy member of the Blue Öyster Cult and as Craig, the pep rally-ready Spartan cheerleader, as well as for his spot-on impressions of George W. Bush, Robert Goulet and Alex Trebek. The musical guest will be the 20-year-old songwriter King Princess, making her “S.N.L.” debut.

THE DISAPPEARANCE OF THE MILLBROOK TWINS 7 p.m. on Oxygen. This two-hour special attempts to unravel a decades-old cold case. In 1990, Dannette and Jeannette Millbrook, 15-year-old twins, went missing near their home in Augusta, Ga. Now, a former federal prosecutor, Laura Coates, and a former homicide detective, Page Reynolds, will re-examine the case, speaking with experts close to the investigation, eyewitnesses, the local authorities and family members.