A couple of unexpected plot turns have resulted in cast changes at Shuffle Along Or The Making of the Musical Sensation of 1921 and All That Followed, the George C. Wolfe show that picked up 10 Tony Awards nominations last week including Best Musical. The show also was named best new musical of the season by the New York Drama Critics Circle.

Star Audra McDonald, who had been set to take a leave from the show beginning shortly after the Tony Awards in June to fulfill a prior acting commitment, announced today that she is pregnant and has postponed the London production of Lady Day at Emerson’s Bar & Grill. McDonald won her record-breaking sixth Tony Award for her 2014 performance as Billie Holiday in the Broadway revival of Lainie Robertson’s show-cum-concert. Instead, McDonald will stay with Shuffle Along until July 24, several weeks longer than originally planned, and return at an unspecified date next winter. McDonald is married to actor Will Swenson (Hair).

Savion Glover & George C. WolfeProducer Scott Rudin said today that McDonald’s replacement will be classically trained singer Rhiannon Giddens, making her Broadway debut. A founding member of the Carolina Chocolate Drops, a Grammy-winning roots-music trio, Giddens’ recent solo album Tomorrow Is My Turn “heralds the arrival of a major American artist,” according to the review site PopMatters.

Rudin also announced that Savion Glover, who choreographed the show and is himself a celebrated tap dancer, will join the company onstage during Giddens’ run. No specifics were given, but it seems likely that Glover will perform special material in collaboration with Wolfe, who also conceived and wrote the show.