NBC said Thursday that Fey, former "SNL" cast member and head writer, is hosting the April 10 show and will be joined by pop star Justin Bieber.
Phillippe is set to host the April 17 show with Ke$ha as the musical guest. On April 24, "Precious" star and Oscar nominee Sidibe will take on hosting duties and the band MGMT is to perform.
Fey, the star and creator of NBC's "30 Rock," is making her second appearance as host, while Phillippe and Sidibe are first-timers.
Phillippe is in the upcoming film "MacGruber," an adaptation of the "SNL" sketch about a hapless special-ops man, played by Will Forte.