Scarlett Johansson, Reese Witherspoon and Louis C.K. have been booked as guest hosts for the last three episodes of Saturday Night Live's milestone 40th season, NBC announced.
Johansson will appear on the May 2 edition of the sketch comedy program when Wiz Khalifa makes his SNL debut as musical guest.

Witherspoon will star in the May 9 episode and Florence + the Machine will provide the musical entertainment.

Louis C.K. will host the SNL season finale on May 16 when recording artist Rihanna will perform.