Stern to help Letterman mark 30-year milestone NEW YORK, Jan. 26 (UPI) -- U.S. radio icon Howard Stern will help David Letterman celebrate 30 years in late-night television next week, CBS said Thursday. Stern is to make his 21st appearance on Letterman's "Late Show" Wednesday. He previously was a guest 20 times on Letterman's "Late Night" show on NBC. "As of Feb. 1, 2012, David Letterman will have hosted 5,443 shows and welcomed 17,904 guests in his 30 years in late-night television," CBS noted in a news release. He has been credited with redefining the talk-show genre when 'Late Night with David Letterman' premiered Feb. 1, 1982. The groundbreaking show earned five Emmy Awards and 35 Emmy nominations during its 11 1/2 years on the air. Since its debut on CBS on Aug. 30, 1993, the critically-acclaimed 'Late Show with David Letterman' has been honored with nine Emmy Awards.