Keith Urban let loose with a “Yeehaw!” after a standing-room only crowd at Ryman Auditorium leapt to its feet when he took the stage.

He played three songs and an unexpected encore. He was joined by a string quartet on “Long Hot Summer,” then turned down the volume and sang “Making Memories of Us” microphone-free with the audience. His full band then joined him on stage for “You Gonna Fly” and “I Wanna Love Somebody Like You.”

Urban didn’t address the surgery while speaking with the crowd.

The 44-year-old Australian had a polyp removed from a vocal cord last November. His last public performance was at a taping for the “CMA Country Christmas” television special in mid-November. The surgery forced Urban to postpone the tail end of his 2011 tour and his “All For The Hall” benefit for the Country Music Hall of Fame. That star-studded event is now being held April 10.