Though they never made a big deal out of it, George Lucas and Steven Spielberg had a friendly alien cameo game that they shared when it came to the characters of E.T. and Yoda. The story goes that when Spielberg inserted a Yoda reference into E.T., Lucas promised an E.T. reference when he got around to making his next Star Wars movie. As such, you can clearly see a trio of creatures that look exactly like the one featured in E.T. during the Galactic Senate scene in Star Wars Episode I.
Neither director ever went out of their way to confirm that, yes, E.T. is a creature from the Star Wars universe, but these images -- coupled with the fact that when E.T. spots a Yoda costume in the film, he immediately starts saying "Home! Home! Home!" -- kinda says it all without actually saying it all. Here's more on the alien, known in the Star Wars universe as "The Children of the Green Planet," from Wookieepedia.
We dug up both references on YouTube for you to check out for yourself.
E.T. - The Extra Terrestrial (watch for the Yoda cameo at 2:20)
Star Wars Episode 1: The Phantom Menace (watch for the E.T. reference in the left-hand corner of your screen at 1:37)
What do you think? Does it change anything for you knowing E.T. actually exists within the Star Wars universe, or do you only see this as a clever nod to a buddy and not some giant cinematic revelation?