Harry Styles is serving as both host and musical guest ...

Saturday Night Live is a new episode tonight, with a huge guest host who is also performing as the musical guest.

Tonight's headliner is the third heartthrob in as many weeks to take the Studio 8H stage — both stages, in this case.

"Saturday Night Live" is set to air its 19th and final episode of Season 50 this weekend, with its host making her second appearance on the iconic late-night show. This Saturday's episode will be ...