John is scheduled to host April 2 and will pull double duty as he'll also perform with musical guest Leon Russell. John's only previous appearance on the sketch show came in 1982 as a musical guest. John and Russell recently released an album titled The Union.
Mirren will take the stage April 9 with musical guest The Foo Fighters, who return for a seventh appearance. The Oscar winner can be seen in the movie remake of Arthur, starring Russell Brand, out in theaters April 8.
What do you think of SNL's April lineup?