01/27/2014 AT 09:30 AM EST
Things are getting weird in Keith Urban
Or at least that's what his 5-year-old daughter with Nicole Kidman
, Sunday Rose
"Every week there's something new going on. There's a new move," Urban, 46, explained on the red carpet at the Grammys – where he was nominated for best country duo/group performance for "Highway Don't Care" with Taylor Swift
and Tim McGraw
. "There's a new word in their vocabulary. Right now for Sunday, everything's 'that's weird.' "
He continued, "Everything's weird for a 5-year-old ... sometimes she's right!"
Sunday Rose and younger sister, 3-year-old Faith Margaret
– who are "growing rapidly" according to Urban – weren't onhand to witness their father's spot on Sunday evening, where he performed "Cop Car" with Gary Clarke Jr.