Here is the reason for that "endless laughing." In 1969, while singing Are You Lonesome Tonight during a concerrt at the International Hotel in Las Vegas, Elvis changed a line. Instead of "Do you gaze at your doorstep and picture me there?" he sang, "Do you gaze at your bald head and wish you had hair?" Then a man in the audience removed his toupee and Elvis started laughing and lost his composure. He's backed by the Sweet Inspirations here.