Garth Brooks and Trisha Yearwood are honoring the late U.S. President Jimmy Carter. The country music icons performed Thursday at his funeral in Washington, D.C. They sang, “Imagine,” by John Lennon. The couple was asked to appear due to their close friendship with the Carters and their work together with Habitat for Humanity. President Carter died on December 29th at his home in Plains, Georgia. He was 100-years-old.