The 'Need You Now' hitmaker welcomed a daughter with husband Chris Tyrrell on Monday (22.07.13), and the couple have named the newborn Eisele Kaye.
Hillary announced the news on her Twitter page by writing: ''She's here, and we are in HEAVEN!!! Eisele Kaye, our beautiful angel, HAPPY BIRTHDAY!!! (sic)''
The 27-year-old country star announced her pregnancy in December and discovered she was expecting a daughter in March.
She wrote in December: ''Chris & I are excited to announce that our Christmas gift has arrived a little early this year!#We are having a BABY! We feel so blessed!!! (sic)''
Hillary wed Chris - who is a drummer for Lady Antebellum - in January 2012 after dating for just over two years.
The couple first got together in July 2010 and Chris joined Lady Antebellum's full-time band in October 2011.
A message on the official Lady Antebellum Twitter page reads: ''Congratulations to @HillaryScottLA and Chris, parents of the beautiful Eisele Kaye! Happy birthday and we love you!! (sic)''
There are currently five separate teams working on 'Game of Thrones' projects at HBO.
She's a big fan of the band and this week she got to perform with them.