This is one of the greatest videos on YouTube, even with the presence of Jay Leno.

Back in 1990, Late Night with David Letterman was at the peak of its success and Johnny Carson had two more years ahead of him as host of The Tonight Show (Leno is guest - hosting this night). Paul Shaffer and The Late Show Band, a.k.a. 'The World's Most Dangerous Band,' joined forces with the legendary Doc Severinsen and The Tonight Show Orchestra. The two powerhouses jammed together on the full version of Late Night's theme, which was Grammy - nominated that year.

Paul Shaffer calls this 'the merging of East and West,' as Late Night was in New York and The Tonight Show was in Burbank, California. This is probably very much what The Tonight Show with David Letterman would have sounded like. It's an incredible display of musical collaboration among two generations of musicians and their very different sounds and styles.

You can see these guys put their hearts, souls, and bodies into the music and the performance. Even if you're way too young to know who these people are, you can't deny their talent and the power of this performance.