It was David Letterman's 30 year anniversary on late night television Wednesday, and who better to celebrate it with than his old pal Howard Stern?

As he usually does, Stern tried to get Letterman to criticize late night rival Jay Leno, this time by telling Letterman that he still refuses to do Leno's 'The Tonight Show,' even though Stern now works on fellow NBC program 'America's Got Talent,' because he remains loyal to Letterman. This leads to Letterman taking some shots at his old foe. Is the late-night war back on?

It took a bit of prodding, but Stern eventually got Letterman to trash Leno, and admit that he likens Jay to mass murderer Charles Manson. Much to everyone's delight, Letterman also whipped out his high pitched impersonation of Leno.

Then -- as if to put a damper on Letterman's anniversary fun -- Stern stood up and reminded everyone that a couple years ago Letterman shot a Super Bowl ad with Leno and Oprah Winfrey, another one of Dave's bitter TV rivals. Since evidence of the spot exists on the Internet for all to see, Letterman was just forced to sheepishly admit to it. Check it out below.

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