Daniel John Cook Jr. (August 12, 1926 – July 3, 2008) was a sports writer for the San Antonio Express-News for 51 years. He is most notable for making the phrase "the opera ain't over 'til the fat lady sings" into common use. Described as a "sports icon", Cook started working at KENS in 1956 and continued to work at the television station until 2000. For most of these years, the TV station was owned by the San Antonio Express-News.