'There's No Business Like Show Business' for Regis Philbin and David Letterman

After morning chat show staple Regis Philbin announced his forthcoming retirement, the always jovial Live host called his friend and fellow TV host David Letterman's Late Show on January 18 to discuss his decision. While Letterman lovingly berated Philbin, the show biz veteran asked Dave to help send him off in style by joining in a duet of the Irving Berlin classic "There's No Business Like Show Business" from Annie Get Your Gun. Take a look below!