The couple met as dance partners during the Tony Award-winning run of the hit musical Memphis.
Dugger III proposed while the two actors were recently on vacation in the Dominican Republic. McKay told Playbill.com, "Preston is a true romantic and set up a private dinner for two on the beach, complete with rose petals, champagne and cheesy love songs in the background. He told me he had asked my parents for their blessings and popped the question right at the top of dinner. He couldn't wait any longer!"
The two plan to marry Sept. 29, 2014, which is a Monday, traditionally a day off for Broadway actors. They will be wed in the New Jersey backyard of McKay's parents.
"[Preston] has completely swept me off my feet, and they haven't touched the ground since we began dating almost three years ago," added McKay.
McKay and Dugger (top of the stairs) onstage in Memphis
Holed up in a seedy motel on the edge of the Mojave Desert, two former lovers unpack the deep secrets and dark desires of their tangled relationship, passionately tearing each other apart. Led by director Daniel Aukin (Back Back Back at MTC, 4,000 Miles), Tony winner Nina Arianda (Venus in Fur at MTC, Born Yesterday) and Sam Rockwell (A Behanding in Spokane, The Way Way Back) bring an explosive intensity to Sam Shepard’s (Buried Child, True West) landmark myth of the new Wild West.