Joy Williams and John Paul White
02/13/2012 AT 01:15 PM EST
– and a baby! – for The Civil Wars
The duo's female half, Joy Williams, announced her pregnancy
on Friday by Tweeting, "Beyond elated to share that [husband] Nate [Yetton] & I are expecting our first child in late June!!! My baby bump & I will see you on the red carpet."
Williams, 29, and partner John Paul White picked up awards for best folk album and best country duo/group performance at Sunday's show
"I'm feeling butterflies but I can't tell if it's my baby kicking or the actual butterflies itself," she said backstage, joking that she's a "human bakery". "Both sensations are really, really wonderful."
Williams and White, who formed their band in 2008, hit the public eye when their song "Poison & Wine" was featured on Grey's Anatomy
Widening their audience with a 2011 stint opening for big Grammy winner Adele
, the duo performed their hit "Barton Hollow" on the Staples Center stage before introducing pal Taylor Swift
The Civil Wars collaborated with the singer and composer T-Bone Burnett for "Safe & Sound," the first song from The Hunger Games
soundtrack, premiering Monday evening on MTV.