Now they've gone and won yet another GRAMMY, this time for Best Country Duo/Group Performance for their song "From This Valley." The win is significant, as they won in a category against such country stalwarts as Little Big Town (who won it last year and were again nominated this year for "Your Side of the Bed"), Vince Gill and Kelly Clarkson ("Don't Rush"), Kenny Rogers and Dolly Parton ("You Can't Make Old Friends"), and the powerhouse triple threat of Tim McGraw, Taylor Swift and Keith Urban, who performed together on McGraw's huge No. 1 hit of last year, "Highway Don't Care."

The Civil Wars' win occurred during a non-televised portion of the GRAMMY ceremony, though White did appear in person to accept the award. Williams was not present, though she did tweet her excitement last night and also noted that she was home taking care of her son "who is sick today."

At the podium, White did not thank or even mention his former musical partner Williams, who cowrote the song with White (and Phil Madeira). White did, though, give a shout out to one of the other nominees. "I want to apologize to Dolly Parton for depriving her of anything at all," he said during his acceptance speech. "She's one of my biggest heroes, and it's an honor to be nominated with everyone in this category."

On Monday, however, White, in a series of tweets, offered an apology for his omission of Williams and others during his time at the mic. He said he was "surprised by the win" and was in "multiple states of shock," yet that that's "no excuse" for not acknowledging others who contributed to the song.