In a galaxy far, far away (actually it's just 1980, but it feels that way), there was a duet sung by R2-D2 and a certain singer named John Bongiovi. It was John's first professional recording ever.
John Bongiovi? If that sounds suspiciously familiar, it's because he later became famous as Jon Bon Jovi.
Listen at Jon Bon Jovi singing the lead vocal on the song "R2-D2 We Wish You A Merry Christmas" over at Fanboy: Link [embedded YouTube]