Carrie Underwood is remembering a beloved collaborator.

The “Before He Cheats” singer shared a touching tribute after Brett James—who co-wrote her 2005 song “Jesus, Take the Wheel”—died in a plane crash in North Carolina on Sept. 18.

“Some things are just unfathomable,” Underwood began in an Instagram post Sept. 19. “The loss of Brett James to his family, friends and our music community is too great to put into words.”

“Brett’s passing is leaving a hole in all of us that I fear won’t ever go away,” she wrote. “It will forever be a reminder that this life is but a moment…we have to make the most of each day we’re given here on earth. Each day is a gift.”

Underwood, 42, went on to share some of her favorite memories with James, 57, who she called the “epitome of ‘cool'” and a “good guy.”

That’s especially true when it came to their working relationship, which earned him a Grammy Award for Best Country Song and her for Best Female Country Vocal Performance for “Jesus, Take the Wheel.”