McDonald is currently starring as Bess in the Broadway revival of Porgy and Bess. Swenson is among the three stars of the Broadway musical Priscilla Queen of the Desert.
The two first appeared together in the 2007 Broadway revival of 110 in the Shade, in which McDonald starred as Lizzie. Swenson understudied the leading role of Bill Starbuck. They also co-starred in a 2009 benefit production of the musical at the Hale Center in Utah.
McDonald's publicist did not release any additional details, but did note the Broadway couple were very happy to announce their engagement.
McDonald is a four-time Tony Award winner for Carousel, Master Class, Ragtime and A Raisin in the Sun. She was Tony-nominated for Marie Christine and has appeared in Henry IV, the Actors Fund concert of Dreamgirls and the Shakespeare in the Park production of Twelfth Night. On screen she has been seen in "A Raisin in the Sun," "Private Practice," "Annie" and "Wit," among others.