David Letterman made a brief comeback to the talk show concept

If you watched American talk shows in the 90s, you'll surely remember the feuds between former good friends Jay Leno and David Letterman, who each had their own talk show. Leno usually drew a bigger audience with The Tonight Show, but many argued that Letterman's Late Show was far smarter and simply better.

Both have long since left the talk show circuit and their programs have been taken over by Jimmy Fallon and Stephen Colbert, but the day before yesterday we were treated to a nice dose of nostalgia. David Letterman showed up unannounced at Fallon's to great cheers from the audience, and since the house band The Roots was busy elsewhere, Paul Shaffer (Letterman's old sidekick and bandleader) was stand-in, which meant a really heartfelt reunion of the duo.

If you know all the twists and turns between Leno and Letterman and followed this talk show giant when it happened, check out the clip below. A delightful, nostalgic and - most importantly - fun moment is promised.