Mulaney will take the reins on Feb. 29, but accepting the gig required him to cancel a stand-up engagement he had planned.
"I am terribly sorry to move the show again. It is now rescheduled for April 10. I will be there no matter what. I love you Toronto. Also I'm afraid of Lorne so I do what he says," Mulaney tweeted, referring to SNL boss Lorne Michaels.
Former Talking Heads lead singer David Byrne will also perform on SNL Feb. 29.
Craig will host the March 7 edition of the show when singer-songwriter The Weeknd will provide the musical entertainment.
Craig's next James Bond adventure No Time to Die is due in theaters on April 10.