What’s on TV

THE MASKED SINGER 10:30 p.m. on Fox. You may ask yourself two questions while watching this vocal competition: Who’s behind the mask, and how can they breathe in that thing? The series, back for Season 3, has celebrities compete against one another by belting out pop songs while decked out in elaborate disguises. The contestants’ identities are only revealed after they are voted off the show. (Previous singers include a shimmering butterfly and a fox in a top hat.) Nick Cannon returns as host, joined by the panelists Ken Jeong, Jenny McCarthy, Nicole Scherzinger and Robin Thicke.

GREAT PERFORMANCES AT THE MET: MADAMA BUTTERFLY 12 p.m. on PBS (check local listings). The film director Anthony Minghella revives this timeless opera by Puccini. The soprano Hui He plays the title role, a geisha waiting for her American husband (Bruce Sledge) to return to Japan in the early 20th century. Pier Giorgio Morandi conducts.