Late night TV host David Letterman devoted a segment of his TV show last night to talking about CBS Radio’s long-running morning newscast, World News Roundup, recounting his devotion to listening to the daily program as he drives his son to kindergarten. Apparently unhappy with one recent change in the morning news broadcast, Letterman decided to phone Roundup anchor Steve Kathan and asked him to return to the program’s signature time check and cutaway cue, “Time on the Roundup, eight past the hour.” This morning, Kathan obliged Letterman’s request and sent a shout-out right back at the television talk host and his son. The 10-minute daily CBS World News Roundup is America’s longest-running network newscast. It debuted in 1938, anchored by veteran newscaster Robert Trout, with reports from Edward R. Murrow in London and William L. Shirer in Berlin as America prepared for the onslaught of World War II. Roundup currently airs daily at 8am (ET) and again at 7am (PT).